12 Common English Words You’re Probably Using Wrong

English has earned a reputation for being unusually difficult, and the words on this list help explain why. Over centuries of Old English roots, French influence, shifting pronunciation, and everyday misuse, some familiar words have developed meanings that are confusing, contradictory, or far removed from where they began. A few can even mean two opposite things depending on how they are used.

Linguists often call these contronyms or Janus words, a reference to the two-faced Roman god who looks in opposite directions at once. Because their meanings depend so heavily on context, they can create uncertainty in legal documents, news headlines, instructions, and ordinary conversations.

Most of the time, the surrounding sentence makes the intended meaning clear. Sometimes, however, even context is not enough. Here are 12 English words that may mean the opposite of what you think.

The word "sanction" is commonly used in two distinct ways. It can mean "approval," as in "the committee sanctioned the project." But it can refer to punishment imposed on a nation or individual, as in "international sanctions were imposed on the regime." What makes the situation a bit more complicated, however, is the fact that both uses of the word "sanction" are equally correct despite being complete opposites of each other.

The word came into the English language from the Latin word sanctio, originally meaning a formal binding decree or law. In time, "sanction" was used for two different cases, either for authorization or as a legal penalty. Both uses persist to this day, so diplomats authorize sanctions, meaning restrictions on trade, while administrators strive for sanctions by securing their authorization. The word carries its own contradiction into every sentence it appears in.

"Cleave" means both to split apart and to cling together. A butcher cleaves a beast down the middle, while a terrified child cleaves to his parent's side. Both sentences are grammatically correct and semantically opposite.

The explanation here is simple. These are two different words that happen to be spelled the same. "Split" comes from the Old English cleofan, with roots in Proto-Germanic kleuban. The other, "cleave," meaning cling or adhere to, comes from the Old English clifian, with a completely different etymology. They converged in spelling over centuries and have been confusing readers ever since. The Bible uses "cleave" in the unity sense ("a man shall cleave unto his wife"), which has made a lot of readers scratch their heads in confusion.

Most people assume that "restive" means the same as "restful," "settled," or "calm," since these seem like obvious assumptions based on how similar the words are. This is far from accurate. A restive person or animal is difficult to control, resists restraint, or cannot remain still.

The term originated as an Old French word describing horses that refused to move forward: stubborn, resistant, balking. Over time, it evolved to refer to anyone or anything that defies control or becomes agitated by any attempt to contain it. The confusion with "restful" is purely visual and phonetic. The two words share no meaningful connection beyond their first four letters. A restive crowd is not a calm one. It is one on the edge of breaking loose.

If you ask an English speaker what the meaning of nonplussed is, you would likely get an answer along the lines of unbothered, unmoved, unimpressed, or unfazed. This is precisely the opposite meaning of nonplussed. Nonplussed means so surprised and confused that you don’t know how to react. You are speechless with bewilderment. Absolutely baffled.

This term comes from the Latin non plus, which means "no more" or "no further," the idea that you have been brought to a standstill. The original meaning of the English word, which dates back to the 16th century, conveyed utter disorientation.

At some point during the 20th century, the "non-" prefix was misread by American speakers as a straightforward negation, which led to the folk definition of "not-plussed," or unfazed. This erroneous interpretation has become so widespread that it has even made its way into some American dictionaries. There, both uses are defined with a note explaining the historical confusion.

The common use of "peruse" means to take a quick look at something. One peruses a menu, peruses magazines, or peruses a bookshelf. What the word actually means, however, is to take a close and thorough look at something.

The word originated from Middle French, and for several centuries, it was only used to mean a careful review of something. Over time, the casual meaning of taking a quick peek at something developed alongside the original. Both meanings have been documented since at least the 16th century, but earlier usage guides maintained that "careful reading" was the proper one, while "skimming" was incorrect.

Now, according to Merriam-Webster, both uses are listed, noting that the two meanings have coexisted for roughly four hundred years. This leads to some confusion. For example, if a person "perused the contract," there is no way to know whether they read every single clause or if they barely glanced at the cover page.

When we describe something as terrific, we are usually paying it a compliment. If things are going your way, you’ve had a terrific dinner, a terrific show, a terrific day. The positive usage of terrific can be traced back at least until the mid-20th century. But when the word "terrific" entered the English language in the 1660s, it meant "causing terror."

The shared root with "terrify," "terrible," and "terror" is not a coincidence, since all four words have their roots in the word terrēre, which means "to frighten." A terrific storm, therefore, refers to a terrifying storm. A terrific roar is supposed to be a scary one. Over time, "terrific" shifted in the same way that "awesome" eventually shifted, losing the edge of fear and becoming a general intensifier for anything that provoked a strong emotional reaction.

"Bemused" is typically used to express mild entertainment. It’s used when you are slightly amused by something. "She watched the chaos with a bemused smile." This example is as poetic as it is wrong.

"Bemused" actually means confused, bewildered, or preoccupied to the point of distraction. There is nothing about entertainment or amusement in its definition. The "muse" in "bemused" comes from an older sense of musing that means becoming absorbed or lost in thought, rather than the modern sense of mild contemplation. The "be-" prefix intensifies it. The bemused person will not just be smiling at the distraction but will be significantly confused.

The two meanings got mixed up because "bemused" looks and sounds like a mild form of "amused," and the superficial resemblance was enough to change the word's meaning in common usage. Most style guides will still flag the modern interpretation as being incorrect.

Using the word "enormity" to refer to size is common enough to appear perfectly fine: the enormity of a certain undertaking or the enormity of the known universe. There is something intuitive about the modern use of the word. It feels right. But it is not. Enormity does not mean largeness. It means wickedness, specifically a monstrous or outrageous act.

The word "enormity" comes from Latin, where it meant "out of the normal rule," and the connotations of extreme evil followed the word into English. An enormity was a transgression so severe it fell outside the bounds of normal behavior. The association with size developed from the conflation of horrible acts with the figurative size of their consequences.
But the distinction is not trivial: a sentence like "the president talked about the enormity of the relief effort" means something very different than what the author had in mind. While usage guides fought this battle for over a century, they had limited success. Many dictionaries now list both meanings.

Nowadays, "egregious" is used exclusively to describe something that is shockingly bad. An egregious error or an egregious lie. The word carries unambiguous negative weight in modern usage, but it didn’t start that way. For much of its early history in English, "egregious" meant remarkably good. "Egregious" described someone who stood out from the masses in a very favorable manner.

"Egregious" comes from the Latin egregius, meaning "out of the flock." It’s someone who rises above the rest. Someone who stands out. Early English writers used it as a compliment. 16th-century writers employed it similarly, but somewhere near the end of the century, the use of "egregious" tipped into sarcasm, and the irony wasn’t lost on the readers. But the ironic use of the word became so common that people stopped recognizing it as ironic and began to take it literally. By the 18th century, the positive sense had effectively died and the word became the opposite of what it had previously meant.

"Fulsome" is commonly understood as generous, abundant, or very thorough. A fulsome apology, a fulsome dedication, fulsome praise. The message is always intended as praise. In fact, fulsome means overly flattering, to the point of seeming insincere or insulting. Fulsome praise is not high praise, but praise so exaggerated that it begins to seem questionable.

"Fulsome" comes from the Old English fullsom, and the definition of excessiveness or insincerity dates back to the 13th century. The original meaning was too much of something pleasant until it became unpleasant. The problem is that "full" implies abundance and "some" makes it sound less forceful, giving the impression of something inherently positive. Writing handbooks have been correcting this error for generations. Most people simply ignore this warning and use “fulsome” as a compliment.

"Temper," as a noun, usually refers to emotional volatility. An individual "has" or "loses" his/her temper or has a bad or quick temper. However, when used as a verb, "temper" means to regulate, restrain, or moderate. It means tempering enthusiasm or tempering steel. In other words, the noun and the verb have different emotional impacts.

The verb has a longer history, going back to the Latin temperare, which meant regulating or moderating. When you temper steel, you do it by heating and then cooling the metal at controlled cycles, which hardens it without making it brittle. You can also temper emotions or an argument to bring it under control. The same meaning, applied literally or figuratively.

The meaning of "volatile mood" developed separately from "bad temper" being a shorthand for an imbalanced or unregulated constitution, something that derived from a faulty process. While the use of expressions like 'bad temper' still makes sense, the use of 'to have a temper' has become a casual way to suggest lack of control, which is precisely what tempering is designed to prevent.

Today, the word "awful" means something horrible in quality or nature. But for much of English history, the meaning of "awful" meant exactly what its construction suggests: "full of awe," inspiring reverence or wonder. The presence of God was awful. A mountain range at dawn was awful.

The modern use of the word stems from the connotation of awe, which was not entirely positive either. It implied an element of fear, dread, and reverence much more than wonder. Over time, the fearful dimension of awe strengthened, and "awful" gradually drifted toward purely negative territory while "awesome" preserved more of the positive wonder sense, at least until it too was diluted into a synonym for "good."