Drinks for all before a fight — devious! (10)
I believe the answer is:
roundabout
'devious' is the definition.
(I've seen this before)
'drinks for all before a fight' is the wordplay.
'drinks for all' becomes 'round' (as in a round of drinks bought for a group).
'before' is a charade indicator (letters next to each other).
'fight' becomes 'bout' (synonyms).
'round'+'a'+'bout'='ROUNDABOUT'
(Other definitions for roundabout that I've seen before include "devious" , "A plaything" , "Indirect" , "More or less" , "Traffic controller" .)