scummy

[ skuhm-ee ]
/ ˈskʌm i /

adjective, scum·mi·er, scum·mi·est.

consisting of or having scum.
Informal. despicable; contemptible: That was a scummy trick.

Origin of scummy

First recorded in 1570–80; scum + -y1
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for scummiest

scummy
/ (ˈskʌmɪ) /

adjective -mier or -miest

of, resembling, consisting of, or covered with scum
dirty, unpleasant, or nasty
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012