for, primarily, the emperor's stepdaughter. The emperor's daughter objected (9)
I believe the answer is:
protested
'objected' is the definition.
The definition and answer can be both to do with communicating as well as being past participle verbs.
Perhaps you can see an association between them that I can't see?
'for primarily the emperor's stepdaughter the emperor's daughter' is the wordplay.
'for' becomes 'pro' (as in being 'pro' or in favour of something).
'primarily' suggests taking the first letters.
'daughter' becomes 'd' (genealogical abbreviation).
The initial letters of 'the emperors stepdaughter the emperors' is 'teste'.
'pro'+'teste'+'d'='PROTESTED'
Can you help me to learn more?
(Other definitions for protested that I've seen before include "Expressed opposition through action or words" , "Uttered words of dissent" , "Dissented, resisted" , "Made objection or complaint" , "Expressed disapproval, objected" .)