Answer two daughters put together (3)
I believe the answer is:
add
'put together' is the definition.
(I've seen this in another clue)
'answer two daughters' is the wordplay.
'two daughters' can mean two replacements for 'daughters'.
'answer' becomes 'a' (abbreviation eg in Q and A).
'daughters' becomes 'd' (genealogical abbreviation for daughters).
'daughters' becomes 'd' (genealogical abbreviation for daughters).
'a'+'d'+'d'='ADD'
(Other definitions for add that I've seen before include "Count up" , "put two and two together" , "Go further" , "Put together - append" , "Reckon" .)