Stiff, cold and unfeeling? Not at first (5)
I believe the answer is:
rigid
'stiff' is the definition.
(synonyms)
'cold and unfeeling? not at first' is the wordplay.
'cold and unfeeling?' becomes 'frigid' (frigid can mean unfeeling or unwelcoming).
'not at first' means to remove the first letter.
'frigid' with its initial letter removed is 'RIGID'.
(Other definitions for rigid that I've seen before include "Hard" , "starched too much?" , "Not flexible" , "Firmly fixed" , "completely" .)