Unthinking, thoughtless.

= inconsult, adj.

Not taking thought, acting without thought or reflection; unreflecting, heedless, unsuspecting… Without construction.

(un-, prefix1 affix 1.)

Of persons, etc.: Not characterized by consideration; acting without deliberation; thoughtless, imprudent, indiscreet, careless.

Thoughtless; inconsiderate.

Of persons, their qualities, etc.: Wanting in deliberation; inconsiderate; hasty or rash. Obsolete.

Thoughtless; unthinking; characterized by want of thought; inconsiderate.

Unconsidering; = inconsiderate, adj. 2.

With implied sense of depreciation: offhand, airy. Now rare.

(un-, prefix1 affix 4.)