The Collaborative International Dictionary of English v.0.48:

Outcast \Out"cast`\, a. [Cf. Sw. utkasta to cast out.]
   Cast out; degraded. "Outcast, rejected." --Longfellow.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Outcast \Out"cast`\, n.
   1. One who is cast out or expelled; an exile; one driven from
      home, society, or country; hence, often, a degraded
      person; a vagabond.
      [1913 Webster]

            The Lord . . . gathereth together the outcasts of
            Israel.                               --Ps. cxlvii.
                                                  2.
      [1913 Webster]

   2. A quarrel; a contention. [Scot.] --Jamieson.
      [1913 Webster]

WordNet (r) 3.0 (2006):

outcast
    adj 1: excluded from a society [syn: friendless, outcast]
    n 1: a person who is rejected (from society or home) [syn:
         outcast, castaway, pariah, Ishmael]

Moby Thesaurus II by Grady Ward, 1.0:

117 Moby Thesaurus words for "outcast":
   DP, Diogenes, Hieronymian, Hieronymite, Ishmael, Jim Crow,
   Timon of Athens, abandoned, alien, anchoress, anchorite, apartheid,
   ascetic, bedridden invalid, cast-off, castaway, chronic poor,
   cloistered monk, closet cynic, color bar, declasse, defenseless,
   depressed class, derelict, desert fathers, desert saints, deserted,
   desolate, disowned, displaced person, division, eremite,
   ethnocentrism, evacuee, evictee, exclusiveness, exile, exiled,
   expatriate, expellee, fatherless, foreigner, forlorn, forsaken,
   friendless, ghetto-dwellers, godforsaken, helpless, hermit,
   hermitess, homebody, homeless, houseless, insularity, insulation,
   invalid, isolation, isolationist, kithless, know-nothingism, leper,
   loner, marabout, motherless, narrowness, out-group,
   outcast of society, outcaste, outcasts, outlaw, outside the gates,
   outside the pale, outsider, pariah, parochialism,
   persona non grata, pillar saint, pillarist, poverty subculture,
   quarantine, race hatred, racial segregation, recluse, refugee,
   reject, rejected, seclusion, seclusionist, segregation, separation,
   shut-in, slum-dwellers, snobbishness, social outcast, solitaire,
   solitary, solitudinarian, stateless, stay-at-home, stranger,
   stylite, the disadvantaged, the dispossessed, the poor,
   the powerless, the underprivileged, tightness, unacceptable person,
   undesirable, unestablished, unfriended, unharbored, unhoused,
   unplaced, unsettled, untouchable, xenophobia