Join female in a predicament (5)
I believe the answer is:
affix
'join' is the definition.
(thesaurus)
'female in a predicament' is the wordplay.
'female' becomes 'f' (abbreviation).
'in' means one lot of letters goes inside another.
'predicament' becomes 'fix' (I've seen this before).
'a'+'fix'='afix'
'f' inserted within 'afix' is 'AFFIX'.
(Other definitions for affix that I've seen before include "Fasten (to something)" , "Append" , "Stick on" , "Attach" , "Glue" .)