Better blooming get your kit off! (8)
I believe the answer is:
outstrip
'better' is the definition.
(better can mean to outstrip or outdo)
'blooming get your kit off' is the wordplay.
'blooming' becomes 'out' (plants which have bloomed are 'out').
'get your kit off' becomes 'strip' (to get your kit off is to strip naked).
'out'+'strip'='OUTSTRIP'
(Other definitions for outstrip that I've seen before include "Surpass, do better than" , "Outrun or surpass" , "Exceed; move faster than" , "Leave behind" , "Move faster than (someone else)" .)