Ridicule father embracing heartless aunt (6)
I believe the answer is:
satire
'ridicule' is the definition.
(I've seen this before)
'father embracing heartless aunt' is the wordplay.
'father' becomes 'sire' (synonyms).
'embracing' is an insertion indicator.
'heartless' means to remove the middle letters.
'aunt' with its centre taken out is 'at'.
'sire' placed around 'at' is 'SATIRE'.
(Other definitions for satire that I've seen before include "Irony and ridicule in speech or writing" , "Humorous criticism of folly or vice" , "Sarcastic humour" , "Humerous literary ridicule" , "text of Juvenal" .)