As an afterthought, and in the middle of feud, goes to party, being phoney (6)
I believe the answer is:
pseudo
'being phoney' is the definition.
(I've seen this before)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for pseudo that I've seen before include "Fake, mock, false" , "Ersatz" , "O dupes! being false and insincere" , "'Fake, sham (6)'" , "Does up, looking phoney" .)