WordNet (r) 3.0 (2006):

tribesman
    n 1: someone who lives in a tribe

Moby Thesaurus II by Grady Ward, 1.0:

42 Moby Thesaurus words for "tribesman":
   agnate, ancestry, blood, blood relation, blood relative, clansman,
   cognate, collateral, collateral relative, connections,
   consanguinean, distaff side, distant relation, enate, family,
   flesh, flesh and blood, folks, german, kin, kindred, kinfolk,
   kinnery, kinsfolk, kinsman, kinsmen, kinswoman, kith and kin,
   near relation, next of kin, people, posterity, relations,
   relatives, sib, sibling, spear kin, spear side, spindle kin,
   spindle side, sword side, uterine kin