Daughter agreed: dreadful disgrace (7)
I believe the answer is:
degrade
'disgrace' is the definition.
(I know that disgrace can be written as degrade)
'daughter agreed dreadful' is the wordplay.
'daughter' becomes 'd' (genealogical abbreviation).
'dreadful' is an anagram indicator.
'agreed' anagrammed gives 'egrade'.
'd'+'egrade'='DEGRADE'
(Other definitions for degrade that I've seen before include "Cheapen, bring disgrace on" , "Disgrace, lower in status" , "Humiliate" , "Shame" , "Break down; debase" .)