Preposterous

Part of speech: adjective

Pronunciation: /pɹɪˈpɒstəɹəs/

Definitions

1. shockingly unreasonable and illogical in a manner that defies all rational understanding
2. Completely lacking sense or logic to the point of seeming laughable or impossible
3. So wildly unreasonable or foolish that it challenges common understanding or belief

Etymology: Before it described anything absurd, "preposterous" literally meant "with the hinder part before." The Latin "praeposterus" joined "prae" ("before") and "posterus" ("coming after"), so the image was of something turned backwards, with the rear end where the front should be. Romans used it for things put in the wrong order, and the sense of reversal stayed in the word for centuries. The jump from physical reversal to moral and intellectual judgment came through the idea that a thing out of its proper sequence is also a thing out of its proper sense. When something is upside down, it looks wrong, and in time the word came to describe claims, behaviour and plans that are not merely mistaken but ridiculously contrary to reason. The shift from literal to figurative is the heart of the word's history.

Synonyms: absurd, ridiculous

Antonyms: reasonable, sensible