Do answer father with love (4)
I believe the answer is:
afro
'do' is the definition.
(type of hairdo)
'answer father with love' is the wordplay.
'answer' becomes 'a' (abbreviation eg in Q and A).
'father' becomes 'fr'.
'with' says to put letters next to each other.
'love' becomes 'o' (In tennis, 'love' means 'zero').
'a'+'fr'+'o'='AFRO'
(Other definitions for afro that I've seen before include "Hairstyle with tight curls" , "Hair in tight curls" , "One cut" , "Of hair style, tightly curled and bushy" , "Type of hairstyle - from Africa" .)