Source : Webster's Revised Unabridged Dictionary (1913)

Derisory \De*ri"so*ry\, a. [L. derisorius: cf. F. d['e]risoire.]
   Derisive; mocking. --Shaftesbury.

Source : WordNet®

derisory
     adj : completely devoid of wisdom or good sense; "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" [syn: {absurd}, {cockeyed}, {idiotic}, {laughable},
            {ludicrous}, {nonsensical}, {preposterous}, {ridiculous}]