Crackpot

Noun

 * 1)  An eccentric, crazy or foolish person. A kook.
 * Time will tell whether he is a crackpot or a genius for promoting that sort of idea.
 * 1)  Someone addicted to crack cocaine (i.e. a drug addict).  See also crackhead.

Synonyms

 * crazy
 * kook
 * live one
 * nut ball
 * nutbag
 * nutbar
 * nutcase
 * nutter

Adjective
crackpot


 * 1)  Eccentric or impractical
 * a crackpot idea

Thesaurus
alien, aliene, bedlamite, borderline case, case, character, crackbrain, crank, cuckoo, dement, demoniac, ding-a-ling, dingbat, eccentric, energumen, erratic, fanatic, flake, fou, freak, harebrain, hermit, hobo, idiot, kook, lone wolf, loner, loon, loony, lunatic, madman, maniac, maverick, meshuggenah, natural, noncompos, nonconformist, nut, odd fellow, oddball, oddity, original, outsider, pariah, phrenetic, queer duck, queer fish, queer specimen, rara avis, raving lunatic, recluse, screwball, solitary, strange duck, tramp, type, weirdo, zealot