(n.) One who leaves, or withdraws.

DP alien arriviste colonist departer displaced person emigre evacue evacuee exile expatriate fugitive gate-crasher goer greenhorn immigrant in-migrant intruder leaver migrant migrator migratory migratory worker new arrival new boy newcomer novus homo out-migrant parvenu recruit refugee rookie settler squatter stateless person stowaway tenderfoot trekker upstart wetback