Set on having a little time on course (6)
I believe the answer is:
attack
'set on' is the definition.
('attack' can be a synonym of 'set on')
'a little time on course' is the wordplay.
'little time' becomes 't' (abbreviation for time).
'on' is a charade indicator (letters next to each other).
'course' becomes 'tack' (I've seen this before**).
'a'+'t'+'tack'='ATTACK'
'having' is the link.
(Other definitions for attack that I've seen before include "attempt at seizure" , "Assault or criticise violently" , "Invade; vilify" , "Strike" , "Brownish pigment" .)