Regularly avoided trouble by withdrawing smear (4)
I believe the answer is:
blur
'smear' is the definition.
('blur' can be a synonym of 'smear')
'regularly avoided trouble by withdrawing' is the wordplay.
'regularly avoided' means one should take alternating letters.
'withdrawing' is a reversal indicator.
'trouble'+'by'='troubleby'
The alternating letters of 'troubleby' are 'rulb'.
'rulb' backwards is 'BLUR'.
(Other definitions for blur that I've seen before include "Indistinct representation - obscure" , "Unclear image, of a pop band" , "Mist" , "Ill-defined smear" , "Pop group; make unclear" .)