1. 
[syn: napping, off-guard(a), off guard(p), off one's guard(p), off his guard, off her guard, off your guard]
WordNet (r) 3.0 (2006):
off guard
    adj 1: not prepared or vigilant; "the blow caught him napping";
           "caught in an off-guard moment"; "found him off his
           guard" [syn: napping, off-guard(a), off guard(p),
           off one's guard(p), off his guard, off her guard,
           off your guard]
Moby Thesaurus II by Grady Ward, 1.0:
38 Moby Thesaurus words for "off guard":
   asleep, culpably negligent, derelict, goofing off, inadvertent,
   inattentive, incautious, laissez-faire, lax, loose, napping,
   neglectful, neglecting, negligent, nodding, noninterfering,
   nonrestrictive, overly permissive, permissive, procrastinating,
   relaxed, remiss, scamping, skimping, slack, sleeping, slighting,
   slurring, unalert, uncautious, uncircumspect, unguarded,
   unprepared, unready, unrigorous, unvigilant, unwary, unwatchful