crazy

adjective, informal

1)

he was acting like a crazy person

Syn:

mad, insane, out of one's mind, deranged, demented, not in one's right mind, crazed, lunatic, non compos mentis, unhinged, mad as a hatter, mad as a March hare; informal mental, nutty, nutty as a fruitcake, off one's rocker, not right in the head, round/around the bend, raving mad, batty, bonkers, cuckoo, loopy, ditzy, loony, bananas, loco, with a screw loose, touched, gaga, not all there, out to lunch, crackers, nutso, out of one's tree, wacko, gonzo

Ant:

sane

2)

Andrea had a crazy idea

Syn:

stupid, foolish, idiotic, silly, absurd, ridiculous, ludicrous, preposterous, farcical, laughable, risible, nonsensical, imbecilic, harebrained, cockamamie, half-baked, impracticable, unworkable, ill-conceived, senseless; informal cockeyed, daft, kooky

Ant:

sensible

3)

he's crazy about her

Syn:

passionate about, (very) keen on, enamored of, infatuated with, smitten with, devoted to; (very) enthusiastic about, fanatical about; informal wild about, mad about, nuts about, hog-wild about, gone on

Ant:

indifferent, apathetic