Webster’s Revised Unabridged Dictionary · 1913
Reckless
Reck′less, a. [AS. recceleás, rēceleás.] 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.
Syn. — Heedless; careless; mindless; thoughtless; negligent; indifferent; regardless; unconcerned; inattentive; remiss; rash.
— Reck′less·ly, adv. — Reck′less·ness, n.