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 quite see how this works, but
'warm' could be 'heat' and 'heat' is found within the answer.
'cold' could be 'c' (abbreviation, eg on taps) and 'c' is found within the answer.
'test' could be 'trial' (synonyms) and 'trial' is found in the remaining letters.
No letters remain.
This explanation may well be incorrect...
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" .)
