Thought"less, adv.
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.
© Webster 1913.