Rebel with pointed object intercepting letter from abroad to the Queen (8)
I believe the answer is:
mutineer
'rebel' is the definition.
(synonyms)
'pointed object intercepting letter from abroad to the queen' is the wordplay.
'pointed object' becomes 'tine' (a tine is a point on a fork).
'intercepting' means one lot of letters goes inside another (I've seen this in other clues).
'letter from abroad' becomes 'mu' (Greek letter).
'to the queen' becomes 'ER' (Elizabeth Regina).
'mu'+'er'='muer'
'tine' put within 'muer' is 'MUTINEER'.
'with' acts as a link.
(Other definitions for mutineer that I've seen before include "Participant in rebellion" , "Seditionist" , "Military rebel" , "One openly rebelling" , "Person rejecting military authority" .)