Bloke, hot, better going outside (4)
I believe the answer is:
Here is my best explanation:
'bloke' is the definition.
(I've seen this before)
'hot better going outside' is the wordplay.
'hot' becomes 'h'.
'better going' becomes 'cap' (I am not sure about this - if you are sure you should believe this answer much more).
'outside' means one lot of letters goes inside another.
'h' placed within 'cap' is 'CHAP'.