A phrase applied to someone that one strongly dislikes. That guy's total bathtub scum—don't hang out with him.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
n. a totally despised person. (see also pond scum, shower scum. Also a term of address.) Look out, bathtub scum, outa my way!
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.