reckless

Acting or done with a lack of care or caution; careless or irresponsible.

Not recking; careless; heedless; inattentive: in a mild sense.

Not recking of consequences; desperately heedless, as from folly, passion, or perversity; impetuously or rashly adventurous.

Synonyms Enterprising, Rash, etc. (see adventurous), incautious, unwary, unconcerned, indifferent, thoughtless. See list under rash.

Inattentive to duty; careless; neglectful; indifferent.