Devoid of (†reason or) knowledge; ignorant.

Irrational; not endowed with reason.

Devoid of understanding; having no intellectual faculty; irrational. Obsolete.

Of a person or animal: not having the faculty of reason, incapable of reasoning. Also: belonging to or characteristic of such a person or animal.

Not having the faculty of reason; = irrational, adj. 1.

Unreasonable, irrational.

Of a person or animal: without the faculty of reason; incapable of reasoning.

Not endowed with reason; = irrational, adj. 1.

Having no rational capability; unreasoning.

Not endowed with reason.

Of a person or animal: without reason, good sense, or sound judgement; irrational.

Originally (of a person): unbalanced, mentally disturbed. Now chiefly (of a situation, event, etc.): confounding, irrational; disturbing.

slang (originally U.S., in the language of rap and hip-hop). Aggressive, irrational, crazy; unpleasant, bad.