WordNet (r) 3.0 (2006):

permissiveness
    n 1: a disposition to allow freedom of choice and behavior [syn:
         permissiveness, tolerance] [ant: restrictiveness,
         unpermissiveness]

Moby Thesaurus II by Grady Ward, 1.0:

92 Moby Thesaurus words for "permissiveness":
   abandon, abandonment, carelessness, charitableness, charity,
   coddling, condonation, connivance, cosseting, culpa,
   culpable negligence, default, dereliction, disregard, easiness,
   easygoingness, failure, favoring, forbearance, generousness,
   gratification, humoring, immoderacy, impotence, imprecision,
   inadvertence, inadvertency, inattention, incontinence,
   indifference, indiscipline, indulgence, intemperance,
   irrepressibility, laches, laissez-faire, lapse, laxity, laxness,
   lenience, leniency, lenity, licentiousness, long-suffering,
   looseness, loosening, magnanimity, mollycoddling, neglect,
   neglectfulness, negligence, noncoercion, nonfeasance,
   noninterference, nonintimidation, nonperformance, nonrestriction,
   obliging, omission, overindulgence, overlooking,
   overpermissiveness, oversight, pampering, patience, pleasing,
   poor stewardship, procrastination, relaxation, relaxedness,
   remissness, riotousness, slackness, slight, sloppiness, softness,
   spoiling, sufferance, tolerance, toleration, unconstraint,
   uncontrol, uninhibitedness, unreserve, unrestraint, unrigorousness,
   unruliness, unstrictness, wantonness, weakness, wildness,
   winking