Cat fight starting late (4)
I believe the answer is:
lash
'cat' is the definition.
(I've seen this before)
'fight starting late' is the wordplay.
'fight' becomes 'clash' (clash is a kind of fight).
'starting late' means to remove the first letter (the word begins later than normal).
'clash' with its initial letter removed is 'LASH'.
(Other definitions for lash that I've seen before include "Hit with a whip" , "cat hair?" , "Fasten with rope; whip" , "Birch" , "Whip or scourge" .)