Expatriate from Northern India gatecrashing party (6)
I believe the answer is:
banish
'expatriate' is the definition.
(thesaurus)
'northern india gatecrashing party' is the wordplay.
'northern' becomes 'n' (abbreviation e.g. N. Ireland).
'india' becomes 'i' (phonetic alphabet: alpha, bravo, charlie etc.).
'gatecrashing' indicates putting letters inside.
'party' becomes 'bash' (term for a party or celebration).
'n'+'i'='ni'
'ni' placed inside 'bash' is 'BANISH'.
'from' is the link.
(Other definitions for banish that I've seen before include "Send into exile" , "Throw out" , "Exile (someone)" , "'Cast out, ostracise (6)'" , "Cast out, ostracize" .)