Party includes Northern Ireland outlaw (6)
I believe the answer is:
banish
'outlaw' is the definition.
(I've seen this before)
'party includes northern ireland' is the wordplay.
'party' becomes 'bash' (term for a party or celebration).
'includes' indicates putting letters inside.
'northern ireland' becomes 'NI' (abbreviation).
'bash' placed around 'ni' is 'BANISH'.
(Other definitions for banish that I've seen before include "Exile in ash-bin" , "Condemn to exile" , "Cast out, ostracize" , "Send (someone) away" , "Expel or expatriate" .)