wacky

adj. strange, odd; crazy, loony, silly (Slang)

Adjective
1. pungent adjectives of disesteem; "gave me a cockamamie reason for not going"; "wore a goofy hat"; "a silly idea"; "some wacky plan for selling more books"
(synonym) cockamamie, cockamamy, goofy, sappy, silly, whacky, zany, unreasonable
(similar) foolish
(classification) colloquialism
2. informal or slang terms for mentally irregular; "it used to drive my husband balmy"
(synonym) balmy, barmy, bats, batty, bonkers, buggy, cracked, crackers, daft, dotty, fruity, haywire, kooky, kookie, loco, loony, loopy, nuts, nutty, round the bend, around the bend, whacky
(similar) insane

(n.)
A soft, earthy, dark-colored rock or clay derived from the alteration of basalt.
  

silly, foolish, kooky, nutty as a fruit cake Lucy sometimes does wacky things - like, one time she sent ice cream in the mail.

Synonyms and related words:
abnormal, absurd, anomalous, apish, asinine, balmy, bananas, barmy, bats, batty, beany, befooled, beguiled, besotted, bonkers, brainless, buffoonish, buggy, bughouse, bugs, cockeyed, cracked, crackers, crank, crankish, cranky, crazed, crazy, credulous, crotchety, cuckoo, daffy, daft, dazed, demented, deranged, deviant, deviative, different, dippy, divergent, dizzy, doting, dotty, dumb, eccentric, erratic, exceptional, fatuitous, fatuous, fey, flaky, flipped, fond, fool, foolheaded, foolish, freaked-out, freakish, fruitcakey, fruity, fuddled, funny, futile, gaga, goofy, gulled, harebrained, haywire, idiocratic, idiosyncratic, idiotic, imbecile, inane, inept, infatuated, insane, irregular, just plain nuts, kinky, kooky, loony, loopy, lunatic, mad, maggoty, maudlin, moronic, nuts, nutty, odd, oddball, off the hinges, off the track, off the wall, peculiar, potty, preposterous, queer, quirky, round the bend, sappy, screwball, screwballs, screwy, senseless, sentimental, silly, singular, slaphappy, strange, stupid, thoughtless, twisted, unconventional, unnatural, wet, whimsical, witless