Benny's cool, not cold (4)
I believe the answer is:
hill
'benny's' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how one could define the other.
'cool not cold' is the wordplay.
'cool' becomes 'chill' (synonyms).
'not' is a deletion indicator.
'cold' becomes 'C' (eg on taps).
'chill' with 'c' removed is 'HILL'.
Can you help me to learn more?
(Other definitions for hill that I've seen before include "See 14" , "Gradient" , "Box ---, Emma picnic site (J.Austen)" , "Incline" , "Raised area of land" .)