Synonyms and related words :
asleep, brash, brazen, brazenfaced, goofing off, hubristic, improvident, imprudent, impudent, indiscreet, injudicious, insolent, napping, nodding, off-guard, overbold, overcareless, overconfident, oversure, overweening, rash, sleeping, temerarious, unalert, uncautious, unchary, unguarded, unprepared, unready, unvigilant, unwary, unwatchful