napping off-guard off guard off one's guard off his guard off her guard off your guard
napping%5:00:00:unready:00 off-guard%5:00:00:unready:00 off_guard%5:00:00:unready:00 off_one's_guard%5:00:00:unready:00 off_his_guard%5:00:00:unready:00 off_her_guard%5:00:00:unready:00 off_your_guard%5:00:00:unready:00
not prepared or vigilant
the blow caught him napping caught in an off-guard moment found him off his guard