Preposterous

prɪˈpɒst(ə)rəs/
adjective
adjective: preposterous
  1. contrary to reason or common sense; utterly absurd or ridiculous.
    “a preposterous suggestion”
    synonyms: absurdridiculousfoolishstupidludicrousfarcicallaughablecomicalrisiblehare-brainedasinineinanenonsensicalpointlesssenselessinsaneunreasonableirrationalillogicalMore

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