Suffer fool leading attack (6)
I believe the answer is:
assail
'attack' is the definition.
('assail' can be a synonym of 'attack')
'suffer fool leading' is the wordplay.
'suffer' becomes 'ail' (ailing is a kind of suffering).
'fool' becomes 'ass' (ass is a kind of fool**).
'leading' says to put letters next to each other.
'ail' after 'ass' is 'ASSAIL'.
(Other definitions for assail that I've seen before include "Go for" , "Make violent attack on" , "Slate" , "Criticize" , "Attack violently and persistently" .)