Same word as foul-mouthed:

base,bawdy,blue,boorish, brutish,cheap,common,crass,crude,dirty, earthy,filthy,foul,foul-mouthed,gross, gruff, immodest, impolite,improper, impure, incult, indelicate, inelegant, loutish,low, lowbred, lowdown and dirty,mean,nasty,obscene, off-color,offens