Joy, auntie perhaps, runs out (7)
I believe the answer is:
elation
'joy' is the definition.
(I know that elation is a type of joy)
'auntie perhaps runs out' is the wordplay.
'auntie perhaps' becomes 'relation' (auntie is a type of relative or relation).
'runs' becomes 'r' (cricket abbreviation).
'out' suggests deleting specific letters.
'relation' with 'r' removed is 'ELATION'.
(Other definitions for elation that I've seen before include "Great happiness and exhilaration" , "State of pleasure about toe-nail" , "State of being delighted or proud" , "Euphoria of toenail" , "Toenail (anag) -- delight" .)