unguarded

Synonyms: accessible artless candid careless casual direct foolhardy frank headlong heedless honest ill-considered impolitic imprudent impulsive incautious indiscreet ingenuous naive offhand rash spontaneous straightforward unalert uncircumspect unconscious undiplomatic unpremeditated unreflective unthinking unvigilant unwatchful unwise vulnerable weak

Antonyms: careful cautious thoughtful