unguarded

from WordNet (r) 3.0 (2006)

unguarded
    adj 1: lacking protection or a guard; "an unguarded gate"; "his
           unguarded queen was open to attack"
    2: displaying or feeling no wariness; "an unguarded remark"

from Moby Thesaurus II by Grady Ward, 1.0

141 Moby Thesaurus words for "unguarded":
      arbitrary, artless, asleep, bare-handed, bluff, blunt,
      born yesterday, broad, brusque, candid, capricious, careless,
      childlike, confiding, culpably negligent, defenseless, derelict,
      direct, downright, explicit, exposed, forthright, frank,
      frankhearted, free, free-speaking, free-spoken, free-tongued,
      genuine, goofing off, guardless, guileless, hasty, heart-to-heart,
      heedless, helpless, imprudent, inadvertent, inattentive,
      incautious, inconsiderate, indiscreet, ingenu, ingenuous, innocent,
      inobservant, involuntary, laissez-faire, lax, loose, naive,
      napping, neglectful, neglecting, negligent, nodding,
      noninterfering, nonrestrictive, off-guard, open, openhearted,
      outspoken, overly permissive, permissive, plain, plain-spoken,
      procrastinating, reasonless, relaxed, remiss, round, scamping,
      simple, simplehearted, simpleminded, sincere, single-hearted,
      single-minded, skimping, slack, sleeping, slighting, slurring,
      straight, straight-out, straightforward, thoughtless, transparent,
      trustful, trusting, unalert, unarmed, unarmored, unattended,
      uncalculating, uncautious, unchecked, uncircumspect, unconscious,
      unconstrained, uncovered, undefended, undesigned, unequivocal,
      unfortified, ungarrisoned, unguided, unintended, unintentional,
      unmeant, unmeditated, unplanned, unpremeditated, unprepared,
      unprompted, unprotected, unpurposed, unready, unreasoning,
      unreflecting, unreserved, unrestrained, unrigorous, unscreened,
      unsheltered, unshielded, unsophisticated, unsuspecting,
      unsuspicious, unthinking, unthought-of, unthoughtful, unvigilant,
      unwarned, unwary, unwatched, unwatchful, unwise, unwitting,
      vulnerable, weaponless