Reckless

Part of speech: adjective (a.)

1. Inattentive to duty; careless; neglectful; indifferent. Chaucer.

2. Rashly negligent; utterly careless or heedless. It made the king as reckless as them diligent. Sir P. Sidney.

Synonyms: Heedless; careless; mindless; thoughtless; negligent; indifferent; regardless; unconcerned; inattentive; remiss; rash. Reck"less*ly, adv. Reck"less*ness, n.