(of persons) so unrefined as to be lacking in discrimination and sensibility
having or revealing stupidity; "ridiculous anserine behavior"; "a dopey answer"; "a dopey kid"; "some fool idea about rewriting authors' books"
having a mental age of three to seven years
insanely irresponsible; "an idiotic idea"
incongruous;inviting ridicule; "the absurd excuse that the dog ate his homework"; "that's a cockeyed idea"; "ask a nonsensical question and get a nonsensical answer"; "a contribution so small as to be laughable"; "it is ludicrous to call a cottage a mansion"; "a preposterous attempt to turn back the pages of history"; "her conceited assumption of universal interest in her rather dull children was ridiculous"
devoid of intelligence
lacking intelligence; "a dull job with lazy and unintelligent co-workers"
not appropriate to the purpose
showing or resulting from lack of judgment or wisdom; "an unwise investor is soon impoverished"
(of especially persons) lacking sense or understanding or judgment