Reminder for daughter (4)
I believe the answer is:
prod
'reminder' is the definition.
(I've seen this before)
'for daughter' is the wordplay.
'for' becomes 'pro' (as in being 'pro' or in favour of something).
'daughter' becomes 'd' (genealogical abbreviation).
'pro'+'d'='PROD'
(Other definitions for prod that I've seen before include "Poke - remind" , "Dig" , "Push with pointed instrument" , "Poke, stimulate into action" , "Incite to action (with a stick?)" .)