Scummy

Adjective

 * 1) Covered in scum.
 * We have to wash your trousers: they're all scummy.
 * 1)  sleazy, worthless, no good
 * 2006, And what a scummy man / just give him half a chance / I bet he'll rob you if he can. - ‘When the Sun Goes Down’, Arctic Monkeys

Thesaurus
abject, abominable, arrant, atrocious, barfy, base, beggarly, beneath contempt, cheap, cheesy, common, contemptible, crappy, crummy, debased, degraded, depraved, despicable, dirty, disgusting, execrable, fecal, feculent, fetid, filmy, filthy, flagrant, flyblown, foliaceous, foliated, foul, fulsome, gaudy, gimcracky, gloppy, grave, gross, gunky, heinous, icky, in layers, lamellar, lamellate, lamellated, lamelliform, laminate, laminated, laminous, leaflike, leafy, little, low, low-down, lumpen, maggoty, malodorous, mangy, mean, measly, membranous, mephitic, meretricious, miserable, monstrous, mucky, nasty, nauseating, nefarious, obnoxious, odious, ordurous, paltry, pathetic, petty, pitiable, pitiful, poky, poor, puky, putrid, rank, reptilian, repulsive, rotten, rubbishy, sad, scabby, scrubby, scruffy, scurfy, scurvy, scuzzy, shabby, shitty, shoddy, slabby, slimy, sloppy, sloshy, sludgy, slushy, small, sorry, spathic, spathose, sposhy, squalid, stratified, stratiform, three-ply, trashy, trumpery, two-for-a-cent, two-for-a-penny, two-ply, twopenny, twopenny-halfpenny, unmentionable, valueless, vile, vomity, wormy, worthless, wretched, yecchy