abject, low, low-down, miserable, scummy, scurvy -- (of the most contemptible kind; "abject cowardice"; "a low stunt to pull"; "a low-down sneak"; "his miserable treatment of his family"; "You miserable skunk!"; "a scummy rabble"; "a scurvy trick")
scummy -- (covered with scum; "the scummy surface of the polluted pond")