A sane person doesn't have any screws loose — in other words, they're free of mental illness and in a reasonable state of mind.

You probably know that the word insane means crazy. Well, the opposite of insane is sane — or not crazy. A sane person is of sound mind and is mentally healthy. Sane people have good judgment, are reasonable, and can tell the difference between what's real and imagined. Whenever someone commits a crime or does something totally outlandish, people usually wonder if they're sane or not.

Definitions of sane

adj mentally healthy; free from mental disorder

“appears to be completely sane
consistent with or based on or using reason
compos mentis, of sound mind
of sound mind, memory, and understanding; in law, competent to go to trial
in her right mind, in his right mind, in their right minds
behaving responsibly
having a clear mind
afflicted with or characteristic of mental derangement
not consistent with or using reason
not reasonable; not showing good judgment
amok, amuck, berserk, demoniac, demoniacal, possessed
frenzied as if possessed by a demon
around the bend, balmy, barmy, bats, batty, bonkers, buggy, cracked, crackers, daft, dotty, fruity, haywire, kookie, kooky, loco, loony, loopy, nuts, nutty, round the bend, wacky, whacky
informal or slang terms for mentally irregular
brainsick, crazy, demented, disturbed, mad, sick, unbalanced, unhinged
affected with madness or insanity
certifiable, certified
fit to be certified as insane (and treated accordingly)
crackbrained, idiotic
insanely irresponsible
crazed, deranged, half-crazed
driven insane
fey, touched
slightly insane
suffering from a form of schizophrenia characterized by foolish mannerisms and senseless laughter along with delusions and regressive behavior
lunatic, moonstruck
insane and believed to be affected by the phases of the moon
maniac, maniacal
wildly disordered
suffering from a disorder characterized by alternating mania and depression
resembling the mania of manic-depressive illness
mentally ill, unsound, unstable
suffering from severe mental illness
non compos mentis, of unsound mind
not of sound mind, memory, or understanding; in law, not competent to go to trial
suffering from paranoia
psychopathic, psychopathologic, psychopathological
suffering from an undiagnosed mental disorder
characteristic of or suffering from psychosis
raving mad, wild
talking or behaving irrationally
suffering from some form of schizophrenia
screw-loose, screwy
not behaving normally
show more antonyms...

adj marked by sound judgment

sane nuclear policy”
consistent with or based on or using reason

Sign up, it's free!

Whether you're a student, an educator, or a lifelong learner, can put you on the path to systematic vocabulary improvement.