Female, adult with two names (3)
I believe the answer is:
ann
'female' is the definition.
(I've seen this before)
'adult with two names' is the wordplay.
'two names' can mean two replacements for 'name'.
'adult' becomes 'a' (abbreviation).
'with' says to put letters next to each other.
'name' becomes 'n' (common abbreviation e.g. on forms).
'name' becomes 'n' (common abbreviation e.g. on forms).
'a'+'n'+'n'='ANN'
(Other definitions for ann that I've seen before include "- - Jones, 1969 Wimbledon champion" , "eg Miss Widdecombe" , "Lady's name" , "... -Margaret (film actress)" , "Ms Widdecombe" .)