Become too warm but not hot? - get stuffed! (7)
I believe the answer is:
overeat
'get stuffed' is the definition.
(I've seen this in another clue)
'become too warm but not hot?' is the wordplay.
'become too warm' becomes 'overheat' (I've seen this before).
'but not' suggests deleting specific letters.
'hot?' becomes 'h' (abbreviation eg on taps).
'overheat' with 'h' removed is 'OVEREAT'.
(Other definitions for overeat that I've seen before include "ignore threat of a big corporation?" , "Stuff oneself silly" , "pig out?" , "Binge" , "Take too much food" .)