WordNet (r) 3.0 (2006):

noncompetitive
    adj 1: not involving competition or competitiveness;
           "noncompetitive positions"; "noncompetitive interest in
           games" [ant: competitive, competitory]

Moby Thesaurus II by Grady Ward, 1.0:

39 Moby Thesaurus words for "noncompetitive":
   coacting, coactive, coadjutant, coadjuvant, coefficient,
   collaborative, collective, collectivist, collectivistic, collusive,
   combined, commensal, common, communal, communalist, communalistic,
   communist, communistic, communitarian, concerted, concordant,
   concurrent, concurring, conniving, cooperant, cooperating,
   cooperative, ecumenic, fellow, harmonious, harmonized, joint,
   mutual, reciprocal, symbiotic, synergetic, synergic, synergistic,
   uncompetitive