असावधान

uncautious, careless

heedless

marked by or paying little heed or attention; --Franklin D. Roosevelt

inadvertent

happening by chance or unexpectedly or unintentionally

inattentive

showing a lack of attention or care

incautious

lacking in caution

reckless

marked by defiant disregard for danger or consequences; ; -Macaulay

unwary

not alert to danger or deception; ; ; - O.J.Campbell

careless

marked by lack of attention or consideration or forethought or thoroughness; not careful

harum scarum

neglectful

not showing due care or attention