(a.) Not cautious; not circumspect; not attending to the circumstances on which safety and interest depend; heedless; careless; as, an incautious step; an incautious remark.

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