Fighting female concealing a warm heart (6)
I believe the answer is:
karate
'fighting' is the definition.
The answer and definition can be both acts as well as being singular nouns.
Maybe you can see an association between them that I don't see?
'female concealing a warm heart' is the wordplay.
'female' becomes 'kate' (I can't explain this - if you can you should believe this answer much more).
'concealing' is an insertion indicator.
'heart' indicates the central letters.
The middle letters of 'warm' are 'ar'.
'kate' placed around 'ar' is 'KARATE'.
Can you help me to learn more?
(Other definitions for karate that I've seen before include "Oriental-style chops" , "Martial art (with chopping?)" , "Unarmed-combat system" , "A taker (anag)" , "SPORT/GAME" .)