The Collaborative International Dictionary of English v.0.48:

Complicity \Com*plic"i*ty\, n.; pl. Complicities. [F.
   complicit['e].]
   The state of being an accomplice; participation in guilt.
   [1913 Webster]

WordNet (r) 3.0 (2006):

complicity
    n 1: guilt as an accomplice in a crime or offense

Moby Thesaurus II by Grady Ward, 1.0:

139 Moby Thesaurus words for "complicity":
   arraignability, arraignableness, artifice, association,
   bipartisanship, blameworthiness, bloody hands, burden, cabal,
   censurability, censurableness, chargeability, coaction,
   coadjuvancy, coadministration, coagency, cochairmanship,
   codirectorship, collaboration, collaborativeness, collectivism,
   collusion, commensalism, common effort, common enterprise,
   communalism, communism, communitarianism, community, complot,
   concert, concord, concordance, concurrence, condominium,
   confederacy, connivance, conspiracy, contribution, contrivance,
   contriving, cooperation, cooperativeness, copartnership,
   copartnery, cotenancy, counterplot, covin, criminality,
   culpability, deep-laid plot, dirty hands, duet, duumvirate,
   ecumenicalism, ecumenicism, ecumenism, engagement, engineering,
   esprit, esprit de corps, fellow feeling, fellowship, finagling,
   finesse, frame-up, game, guilt, guiltiness, guilty conscience,
   harmony, having a part, impeachability, impeachableness,
   implication, inculpation, indictability, indictableness, intrigue,
   involvement, joining of forces, joint chairmanship, joint control,
   joint effort, joint operation, joint ownership, joint tenancy,
   little game, machination, maneuvering, manipulation, mass action,
   morale, mutual assistance, mutualism, mutuality, octet, onus,
   partaking, participation, partnership, peccancy, plot, plotting,
   pooling, pooling of resources, pulling together, quartet, quintet,
   reciprocity, red-handedness, reprehensibility, reproachableness,
   reprovability, reprovableness, rigging, scheme, schemery, scheming,
   septet, sextet, sharing, solidarity, stratagem, suffrage,
   symbiosis, synergism, synergy, team spirit, teamwork, trick, trio,
   triumvirate, troika, underplot, united action, voting,
   web of intrigue, wire-pulling