idiotic

From idiot +‎ -ic.

idiotic (comparative more idiotic, superlative most idiotic)

(of a person or animal) Pertaining to or resembling an idiot; characterised with behaviour resembling idiocy.
(of an action) Having the quality of idiocy; very foolish
Synonyms: stupid, nonsensical
- 2005, Sean Dooley, The Big Twitch, Sydney: Allen and Unwin, page 131:
  Everyone else shifted uncomfortably as this guy continued his derisive laughter and proclaimed my quest the most idiotic thing he'd heard in his life.

pertaining to or resembling an idiot

Arabic: عَبِيط (ʕabīṭ)
Bengali: মূর্খ (bn) (murkho)
Chinese:
Mandarin: 白痴的 (zh) (báichī), 愚蠢的 (zh) (yúchǔn de)
Czech: idiotský (cs)
Danish: idiotisk
Esperanto: idiota (eo)
French: idiot (fr), stupide (fr), idiotique (fr)
Galician: bolonio m, pallouco m, parvo (gl) m, babiolo (gl) m, mascato m, babeco (gl) m, lores m
German: idiotisch (de), blöd (de)
Hindi: मूर्ख (hi) (mūrkh), अहमक़ (ahmaq)
Indonesian: bodoh (id), goblok (id), tolol (id), idiot (id)
Japanese: 馬鹿な (ja) (ばかな, baka na)
Latvian: idiotisks
Ottoman Turkish: بوك (böñ)
Persian: احمق (fa) (ahmaq)
Polish: idiotowaty
Portuguese: idiótico
Russian: идио́тский (ru) (idiótskij), дура́цкий (ru) (duráckij)
Sanskrit: मूर्ख (sa) (mūrkha)
Serbo-Croatian:
Cyrillic: идѝотскӣ

Roman: idìotskī (sh)
Spanish: idiótico
Swedish: idiotisk (sv)
Turkish: saçma (tr), salakça (tr)
Urdu: مورکھ (mūrkh), احمق (ahmaq)
Volapük: diotanik

having the quality of idiocy

Bengali: মূর্খ (bn) (murkho)
Burmese: နှမ်း (my) (hnam:)
Catalan: idiota (ca)
Danish: idiotisk, dum (da)
Dutch: idioot (nl)
Esperanto: idiota (eo)
Galician: bolonio m, pallouco m, parvo (gl) m, babiolo (gl) m, mascato m, babeco (gl) m, lores m
German: idiotisch (de)
Greek:
Ancient: βεβρός (bebrós)
Indonesian: idiot (id)
Latvian: idiotisks
Polish: idiotyczny (pl)
Portuguese: idiota (pt)
Serbo-Croatian:
Cyrillic: идѝотскӣ

Roman: idìotskī (sh)
Spanish: idiota (es)
Swedish: idiotisk (sv), dum (sv)
Volapük: diotik (vo)

English