asinine

adjective3

1. •
   Very foolish; failing to exercise intelligence or judgement or rationality.

   • They danced on silently, softly. Their feet played tricks to the beat of the tireless measure, that exquisitely asinine blare which is England's punishment for having lost America. — 1922
2. •
   (disapproving) Characteristic of an ass (an asshole): objectionably inconsiderate or jerky.
3. •
   Of, pertaining to, or characteristic of donkeys.

   • Don Quixote had put himself but a little way ayont the village of Don Diego, when he encountered two apparent priests, or students, and two husbandmen, who came mounted on four asinine beasts. — 1881