/ dɪˈraɪsɪv; NAmE / (also less frequent de·ri·sory ) adjective
unkind and showing that you think sb/sth is ridiculous :
She gave a short, derisive laugh.
► de·ri·sive·ly adverb
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WORD ORIGIN
mid 17th cent.: from derision , on the pattern of the pair decision , decisive .