exogamous

from WordNet (r) 3.0 (2006)

exogamous
    adj 1: characterized by or fit for fertilization by a flower
           that is not closely related [syn: {exogamous},
           {exogamic}] [ant: {autogamic}, {autogamous}, {endogamic},
           {endogamous}]
    2: pertaining to or characterized by the custom of marrying only
       outside the limits of a clan or tribe [syn: {exogamous},
       {exogamic}] [ant: {endogamic}, {endogamous}]

from The Collaborative International Dictionary of English v.0.48

Exogamous \Ex*og"a*mous\, a. [Exo- + Gr. ? marriage.]
   Relating to exogamy; marrying outside of the limits of one's
   own tribe; -- opposed to {endogenous}.
   [1913 Webster]