preposterous (
http://definr.com/preposterous)
adj : completely devoid of wisdom or good sense; "the absurd
excuse that the dog ate his homework"; "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" [syn:
absurd,
derisory,
laughable,
ludicrous,
nonsensical,
ridiculous]