Severely criticise second strike (4)
I believe the answer is:
slam
'severely criticise' is the definition.
(I've seen this before)
'second strike' is the wordplay.
'second' becomes 's' (common abbreviation).
'strike' becomes 'lam' (to 'lam' means to hit hard**).
's'+'lam'='SLAM'
(Other definitions for slam that I've seen before include "big contract" , "Shut (door) with force" , "Close noisily" , "Taking of twelve or thirteen tricks (bridge)" , "Winning of 12 or 13 tricks at bridge" .)