Dissident republican (True Republican)
One who is not going to sell-out
to the pro British GFA.

someone who often disagrees with you but who has your best interests at heart. Always rejects violence so cannot be called a terrorist or an anarchist. Generally dies young or never leaves the house (see house arrest).
Syntactically - dissident (which is a noun) has no associated verb stem. You cannot 'dissid'. You can do nothing dissidently - there is no associated adjective. In fact the word exists alone as an island in a sea of semantics. Perhaps this is why the meaning of the word has persisted unchanged for such a long time.