(a.) Like a dunce; duncish.

Boeotian absurd airy apish batty beef-brained beef-witted befooled beguiled besotted blockish bovid bovine brainless buffoonish caprid caprine catchpenny chumpish cloddish cockeyed cowish cowlike crass crazy credulous daffy daft dazed deerlike dense dizzy doltish doting dullard dumb duncical duncish empty equestrian equine fat fatuitous fatuous flaky flimsy fond fool foolheaded foolish fribble fribbling frivolous frothy fuddled futile gaga goatish goatlike goofy gross gulled hircine hoggish hoofed horsy idiotic idle imbecile inane ineducable inept infatuated insane irrational klutzy kooky light loony lumpish mad maudlin mindless moronic mulish nugacious nugatory nutty oafish opaque otiose ovine piggish puerile ruminant sappy screwy senseless sentimental shallow sheepish sheeplike silly slender slight sottish stupid superficial swinish thick thoughtless trifling trite trivial ungulate unreasonable unteachable unwitty vacuous vain vapid wacky weak-minded wet windy witless wrongheaded