Source of special gear for comedy performance (4)
I believe the answer is:
skit
'comedy performance' is the definition.
'source of special gear' is the wordplay.
'source of' suggests taking the first letters.
'gear' becomes 'kit' (kit is a kind of gear**).
The first letter of 'special' is 's'.
's'+'kit'='SKIT'
'for' acts as a link.
(Other definitions for skit that I've seen before include "Taking off piece" , "Brief satirical sketch" , "Parodic sketch" , "take-off" , "Lampoon" .)