Definition of preposterous

The word "preposterous" originated in the late 16th century, derived from the Latin prefix "prae-" meaning "before" or "in front of" and the Latin suffix "-posterus" meaning "standing behind" or "following." Its Latin origins suggest a paradoxical or opposite meaning from its modern English usage. In Latin, "prae-posterus" referred to an ox that was born before its time, literally "before-latter," due to premature birth or twinning. This usage suggests that the animal, being "before" in chronological order, was not fully grown, immature, and therefore "reversed" or "opposite" to the normal sequence. Over time, the word evolved in English, with the meaning transforming from its original medical use to a broader and negative connotation of an absurd or completely illogical statement or idea, unconventional or irrational. By the 18th century, "preposterous" was recorded in English dictionaries, with its modern meaning firmly established. The oxymoronic origin of the word has become largely obsolete, but it provides an insightful perspective on the origins and evolution of language and its capacity for transformation over time.