adjective
preposterous
prih-POS-tuh-ruhs
adjective
1
Utterly absurd or unreasonable; going against common sense.
"It's preposterous to think we could finish the project in a single day."
"The claim that the earth is flat is simply preposterous."
How to Use Preposterous
Learner’s notesIn plain EnglishSo ridiculous or unreasonable that it's hard to take seriously.
Common pairings
a preposterous claim
utterly preposterous
Word Forms
more preposterous comparative, most preposterous superlative
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Etymology
From Latin praeposterus, literally "with the back part before" — combining prae- ("before") and posterus ("coming after"), describing something back-to-front or upside down.