Thoughtless
Pronunciation : Thought"less
Part of Speech : adv.
Definition : 1. Lacking thought; careless; inconsiderate; rash; as, a thoughtless person, or act.
2. Giddy; gay; dissipated. [R.] Johnson.
3. Deficient in reasoning power; stupid; dull. Thoughtless as monarch oaks that shade the plain. Dryden. -- Thought"less*ly, adv. -- Thought"less*ness, n.
Source : Webster's Unabridged Dictionary, 1913