adjective, scum·mi·er, scum·mi·est.
- consisting of or having scum.
- Informal. despicable; contemptible: That was a scummy trick.
adjective -mier or -miest
- of, resembling, consisting of, or covered with scum
- dirty, unpleasant, or nasty
adj.1570s, from scum + -y (2). Transferred sense of “filthy, disreputable” is recorded from 1932. Related: Scumminess.