Synonyms of lunatic in English:

lunatic


See US English definition of lunatic

See UK English definition of lunatic

See Spanish definition of loco

noun

1‘a dangerous lunatic’

SYNONYMS
maniac, madman, madwoman, psychopath, psychotic
informal loony, loon, nut, nutcase, nutjob, cuckoo, head case, headbanger, screwball, psycho
British informal nutter
Scottish informal radge
US informal wing nut
informal have a screw loose, have bats in one's belfry, have bats in the belfry

2‘when I'm in a bad mood I drive like a lunatic’

SYNONYMS
fool, idiot, imbecile, moron

adjective

1‘a lunatic prisoner’

SYNONYMS
mad, insane, mentally ill, certifiable, deranged, demented, of unsound mind, out of one's mind, not in one's right mind, sick in the head, not together, crazy, crazed, non compos mentis, unbalanced, unhinged, unstable, disturbed, distracted, stark mad, manic, frenzied, raving, distraught, frantic, hysterical, delirious, psychotic, psychopathic, mad as a hatter, mad as a March hare, foaming at the mouth
British sectionable
informal mental, off one's head, out of one's head, off one's nut, nuts, nutty, nutty as a fruitcake, off one's rocker, not right in the head, not quite right in the head, round the bend, stark raving mad, raving mad, bats, bonkers, cuckoo, cracked, loopy, loony, bananas, loco, dippy, screwy, schizoid, touched, gaga, off the wall, not all there, not right upstairs
British informal barmy, crackers, barking, barking mad, stark staring mad, dotty, batty, round the twist, off one's trolley, as daft as a brush, not the full shilling, up the pole, away with the fairies
North American informal buggy, nutsy, nutso
out of one's tree, meshuga, squirrelly, wacko
Canadian, Australian, New Zealand informal bushed
Australian informal yarra
New Zealand informal porangi
Australian informal have kangaroos in one's top paddock, have kangaroos in the top paddock
ANTONYMS

sane

2‘a lunatic idea’

SYNONYMS
foolish, stupid, silly, idiotic, half-witted, witless, brainless, mindless, thoughtless, imprudent, incautious, irresponsible, injudicious, indiscreet, unwise, unintelligent, unreasonable
ill-advised, ill-considered, impolitic, rash, reckless, foolhardy, lunatic
absurd, senseless, pointless, nonsensical, inane, fatuous, ridiculous, laughable, risible, derisible
informal dumb, dim, dim-witted, dopey, damfool, half-baked, hare-brained, crackbrained, pea-brained, wooden-headed, thickheaded, nutty, mad, crazy, dippy, cuckoo, screwy, wacky
British informal barmy, daft, batty, dotty, gormless
Scottish, Northern English informal glaikit
North American informal dumb-ass, chowderheaded
West Indian informal dotish
ANTONYMS

sensible, wise