The Collaborative International Dictionary of English v.0.48:

non-involvement \non-involvement\ n.
   withdrawing from the activities of a group.

   Syn: non-engagement, nonparticipation.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

non-involvement
    n 1: withdrawing from the activities of a group [syn: non-
         engagement, nonparticipation, non-involvement] [ant:
         engagement, involution, involvement, participation]

Moby Thesaurus II by Grady Ward, 1.0:

86 Moby Thesaurus words for "noninvolvement":
   a wise passiveness, abstention, anythingarianism, avoidance,
   avoiding reaction, circumvention, contemplation,
   contemplative life, cop-out, defense mechanism, do-nothing policy,
   do-nothingism, do-nothingness, dodge, dormancy, duck, elusion,
   elusiveness, equivocation, escape, evasion, evasive action,
   evasiveness, fence-sitting, forbearance, forestalling,
   forestallment, getting around, idleness, immobility, impartiality,
   inaction, inactivity, independence, indolence, inertia, inertness,
   jink, laissez-aller, laissez-faire, laissez-faireism, meditation,
   mugwumpery, mugwumpism, neutralism, neutrality, neutralness,
   nonalignment, noncommitment, nonintervention, nonparticipation,
   nonpartisanism, nonresistance, nonviolence, nonviolent resistance,
   nothingarianism, pacifism, paralysis, passive resistance,
   passive self-annihilation, passiveness, passivism, passivity,
   policy, prevention, procrastination, quiescence, quietism,
   refraining, shunning, shunting off, shy, sidestep, sidetracking,
   slip, stagnancy, stagnation, standpattism, stasis,
   strict neutrality, the runaround, vegetation, vita contemplativa,
   waiting game, watching and waiting, zigzag