1. grimy, defiled. Dirty, filthy, foul, squalid refer to that which is not clean. Dirty is applied to that which is filled or covered with dirt so that it is unclean or defiled: dirty clothes. Filthy is an emphatic word suggesting something that is excessively soiled or dirty: filthy streets. Both dirty and filthy can refer to obscenity: a dirty mind, a filthy novel. Foul implies an uncleanness that is grossly offensive to the senses: a foul odor. Squalid, applied usually to dwellings or surroundings, implies dirtiness that results from the slovenly indifference often associated with poverty: a squalid tenement. 3. base, vulgar, low, shabby, groveling. 4. nasty, lascivious, lecherous. 10. rainy, foul, sloppy, disagreeable, nasty. 12. dull, dark, sullied, clouded. 15. soil, befoul, sully.