Show derision (5)
I believe the answer is:
snort
'show derision' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for snort that I've seen before include "Rough nasal sound of disgust or anger" , "Noisily express indignation" , "little whisky" , "Derisive noise made through nose" , "Make derisive noise" .)