Daughter devoured boyfriend (4)
I believe the answer is:
date
'boyfriend' is the definition.
(thesaurus)
'daughter devoured' is the wordplay.
'daughter' becomes 'd'.
'devoured' becomes 'ate' (I've seen this before).
'd'+'ate'='DATE'
(Other definitions for date that I've seen before include "Stoned fruit" , "Day, month and year" , "Go out with" , "escort" , "Edible fruit with a long woody seed" .)