WordNet (r) 3.0 (2006):

uncoerced
    adj 1: not brought about by coercion or force; "the confession
           was uncoerced" [syn: uncoerced, unforced, willing]

Moby Thesaurus II by Grady Ward, 1.0:

72 Moby Thesaurus words for "uncoerced":
   abandoned, arbitrary, autonomous, discretional, discretionary,
   elective, free, free will, go-go, gratuitous, immoderate,
   incontinent, independent, indulgent, intemperate, irrepressible,
   lax, licentious, loose, nonmandatory, nonrestrictive, offered,
   optional, out of control, out of hand, permissive, proffered,
   rampant, reinless, riotous, self-acting, self-active,
   self-determined, self-determining, spontaneous, unasked,
   unbesought, unbidden, unbridled, uncalled-for, unchecked,
   uncompelled, unconstrained, uncontrolled, uncurbed, unforced,
   ungoverned, uninfluenced, uninhibited, uninvited, unmastered,
   unmeasured, unmuzzled, unpressured, unprompted, unreined,
   unrepressed, unrequested, unrequired, unreserved, unrestrained,
   unrestrictive, unruly, unsolicited, unsought, unsubdued,
   unsuppressed, voluntary, volunteer, wanton, wild, willful