Groom needed at the fight (6)
I believe the answer is:
combat
'the fight' is the definition.
('combat' can be a synonym of 'fight')
'groom needed at' is the wordplay.
I cannot quite see how this works, but
'groom' could be 'comb' (combing is a way of grooming oneself) and 'comb' is located in the answer.
'at' is present in the answer.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for combat that I've seen before include "Battle, warfare" , "type of jacket" , "Battle or fight" , "Fight against; fighting" , "Military fighting" .)