English Word Pairs That Sound Opposite But Arent

The English vocabulary is rich with easily recognizable pairs of antonyms. However, there are exceptions, below are English word pairs that are not antonyms despite containing commonly found opposite prefixes .

Many English antonyms are as simple as they seem: inside & outside, agree & unusual, etc. But prefixes don't always work the way we expect, words don't always retain their original definitions, and morphological similarities don't always correlate with obvious semantic similarities. All of which is to say that English has a lot of pairs of words that sound like they should be antonyms—but they definitely aren't. Here are English pairs that aren't as antonyms as they seem .

English word pairs that are often mistaken for opposites

• Flammable & inflammable
• Progress & Congress
• increase & increase
• Famous & infamous
• Terminate & exit
• Regardless & irregardless
• To and fro

Flammable & inflammable

The existence of flammable makes us assume that the in- of inflammable must mean “ not ”. But in- can also mean “ in, into, to, toward, on, upon ”, and it serves that purpose in inflammable. If something is flammable, it is capable of having a flame in or on it—you can set it on fire. In other words, inflammable is not “ in + flammable ”. It is “ inflame + able ”.

Progress & Congress

Since pro and con mean “ for ” and “ against, ” respectively, it makes sense that progress and congress include the pro and con of any gress. But gress doesn’t mean anything on its own (though technically it’s a variant spelling of both grass and grease). More importantly, the con of pros and cons is shortened from contra, Latin for “ against .” Con- is a prefix meaning “ with ” or “ together ”—essentially, it’s the Latin version of our English co- (con also literally means “with” in Spanish and Italian). Progress and congress come from progressus and congressus, Latin nouns that both come from the verb gradi, meaning “ to walk or step .” So progress is to walk forward, and congress is to walk together.

increase & increase

“Increment” sounds like what you would call excrement that hasn’t left the body. The Latin etymologies of these words are similar—incrementum and excrementum—but they come from different verbs. Incrementum comes from increscere, meaning “to grow in or on” (like increase), and excrementum comes from excernere, “to sift out or discharge” (like excrete).

Famous & infamous

Infamous doesn’t mean “not famous.” It means “ infamous ” (i.e., “famous for bad things”), like its Latin ancestor infamis. You could argue that infamous is the antonym of famous in the sense of “ honored, celebrated ” (as opposed to just “widely known”). Ironically, though, famous also used to mean “ infamous ”—sometimes the terms were even used together for emphasis. For example, the geographer Robert Morden called Thomas Stucley  “that famous infamous English rebel” in a 17th-century book.

Terminate & exit

The Latin verb terminare means “ to mark an end or boundary ,” and exterminare refers to pushing someone or something beyond that boundary. The definitions of terminating and exterminate have evolved beyond terminus, but the links to their Latin ancestors remain: Termination usually marks the end—of a contract, for example—and extermination still involves getting rid of something (though it is now usually accomplished by destruction rather than expulsion).

Regardless & irregardless

Irregardless, which simply means “ regardless ,” may be the English language’s most notoriously mistaken antonym. But it’s not new: People have been using the term since at least the late 18th century, and Merriam-Webster added it to its dictionary nearly a century ago. The Oxford English Dictionary suggests that it’s “ probably a blend of irrespective and regardles s,” but Merriam-Webster has a different theory—that ir- is acting as an intensifier to actually highlight the absence of regard.

To and fro

Using prefixes to augment the meaning of words is a fairly common linguistic tendency, especially for words that indicate a lack or cancellation. Unthaw, meaning “to thaw,” is a good example. Thaw means “to unfreeze,” but there is nothing in the word itself to suggest that an action—freezing—is being reversed. So people sometimes (though unintentionally) add un- to enhance the sense of negation. Similarly, peeling an orange involves removing the peel—but the verb peel doesn’t do much to convey removal, so unpeel emerged as an alternative. It simply means “to peel.”