Profit by Republican in rebellious mood being guest of Tea Party (8)
I believe the answer is:
dormouse
'guest of tea party' is the definition.
(ref to the dormouse in Alice in Wonderland)
'profit by republican in rebellious mood' is the wordplay.
'profit' becomes 'use' (I've seen this before).
'by' says to put letters next to each other.
'republican' becomes 'r' (abbreviation).
'in' means one lot of letters goes inside another.
'rebellious' indicates an anagram.
'mood' is an anagram of 'domo'.
'r' going into 'domo' is 'dormo'.
'use' after 'dormo' is 'DORMOUSE'.
'being' acts as a link.
(Other definitions for dormouse that I've seen before include "Small British rodent" , "Partygoer" , "Animal" , "Ditto" , "Rodent that sleeps most of the day" .)