The Collaborative International Dictionary of English v.0.48:

Newcomer \New"com`er\, n.
   One who has lately come.
   [1913 Webster]

WordNet (r) 3.0 (2006):

newcomer
    n 1: any new participant in some activity [syn: newcomer,
         fledgling, fledgeling, starter, neophyte,
         freshman, newbie, entrant]
    2: a recent arrival; "he's a newcomer to Boston"

Moby Thesaurus II by Grady Ward, 1.0:

61 Moby Thesaurus words for "newcomer":
   abecedarian, alien, alphabetarian, amateur, apprentice, arrival,
   arriviste, articled clerk, baby, beginner, boot, catechumen,
   colonist, colt, comer, deb, debutant, emigrant, entrant, fledgling,
   foreigner, freshman, gate-crasher, greenhorn, greeny, ignoramus,
   immigrant, in-migrant, incomer, inductee, infant, initiate,
   intruder, learner, neophyte, nestling, new arrival, new boy,
   novice, novitiate, novus homo, outlander, outsider, parvenu,
   postulant, probationer, probationist, proselyte, raw recruit,
   recruit, rookie, settler, squatter, stowaway, stranger, tenderfoot,
   trainee, tyro, upstart, visitant, visitor