Stage warm and later cold during test (10)
I believe the answer is:
theatrical
'stage' is the definition.
(thesaurus)
'warm and later cold during test' is the wordplay.
I cannot really see how this works, but
'warm' could be 'heat' and 'heat' is found within the answer.
'cold' could be 'c' (eg on taps) and 'c' is found in the answer.
'test' could be 'trial' (synonyms) and 'trial' is found within the leftover letters.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for theatrical that I've seen before include "Stagy" , "Showbiz" , "affected" , "Relating to acting/actors" , "Artificial and exaggerated" .)