Ginger's stupid laugh (7)
I believe the answer is:
snigger
'laugh' is the definition.
(sniggering is a kind of laughing)
'ginger's stupid' is the wordplay.
'stupid' is an anagram indicator (in a stupid order).
'gingers' is an anagram of 'SNIGGER'.
(Other definitions for snigger that I've seen before include "Dirty laugh" , "Laugh in a scornful way" , "Half-suppressed laugh" , "Laugh mockingly" , "Laugh slyly" .)