Antonyms for slick

adept:

awkward, inept, unskilled, incompetent.

adroit:

dense.

artful:

artless, naive, unskillful, ingenuous.

canny:

silly, foolish.

clever:

senseless, ignorant, idiotic.

crafty:

honest.

cunning:

shy, kind, gullible.

deceitful:

faithful, trustworthy, truthful, sincere, upright, frank, loyal, open.

slick:

amateurish, unpolished, stupid, unintelligent, unclever, clumsy, coarse, rough.

smart, clever:

slow, simple.

smooth, polished:

dull, dry.

noun:

nonslippery, unstudied, middling, unforced, low-grade, second-rate, bad, forthright, frank, pathetic, simpleminded, unconcealed, rough, execrable, uneven, obvious, outspoken, plain, unsophisticated, mediocre, open, unworldly, candid, trustful, impressionable, roughened, terrible, direct, implausible, patent, childlike, Undesigning, vile, coarsened, trusting, atrocious, rotten, straightforward, awful, plainspoken, aboveboard, wretched, public, unvarnished.