Expert makes a witty remark (5)
I believe the answer is:
crack
This could be a double definition.
'expert' is the first definition.
(as in 'a crack team')
'a witty remark' is the second definition.
'crack' can be an answer for 'remark' (crack is a kind of remark). I'm unsure of the 'a witty' bit.
'makes' acts as a link.
Can you help me to learn more?
(Other definitions for crack that I've seen before include "First-rate" , "Opening; sharp blow" , "Go for expert" , "Narrow opening; joke" , "Fracture" .)