Preposterous

prɪˈpɒst(ə)rəs/
adjective
adjective: preposterous
  1. contrary to reason or common sense; utterly absurd or ridiculous.
    “a preposterous suggestion”
    synonyms: absurd, ridiculous, foolish, stupid, ludicrous, farcical, laughable, comical, risible, hare-brained, asinine, inane, nonsensical, pointless, senseless, insane, unreasonable, irrational, illogical; More

    antonyms: reasonable, sensible
Origin
mid 16th century: from Latin praeposterus ‘reversed, absurd’ (from prae ‘before’ + posterus ‘coming after’) + -ous.