Joy, family member, runs away (7)
I believe the answer is:
elation
'joy' is the definition.
(I know that elation is a type of joy)
'family member runs away' is the wordplay.
'family member' becomes 'relation' (a relation or relative).
'runs' becomes 'r' (cricket abbreviation).
'away' is a deletion indicator.
'relation' with 'r' taken away is 'ELATION'.
(Other definitions for elation that I've seen before include "There's great joy" , "Transport" , "'High spirits, exhilaration (7)'" , "Feeling of intense delight" , "State of pleasure about toe-nail" .)