derisive
adjective /dɪˈraɪsɪv/
  /dɪˈraɪsɪv/
(also less frequent derisory)
- unkind and showing that you think somebody/something is silly
- She gave a short, derisive laugh.
 - His voice was savagely derisive.
 
Oxford Collocations DictionaryDerisive is used with these nouns:- laugh
 - laughter
 - snort
 - …
 
Word Originmid 17th cent.: from derision, on the pattern of the pair decision, decisive.