1. One's close or closest friend; a friend one holds dear to one's heart. We grew up right next door to each other, so we have been bosom chums since we were kids.
2. Lice on one's body. Ugh, I'm so itchy—I really hope my bosom chums aren't back.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
bosom chumsand bosom friends
n. lice. The old guy sat there scratching at his bosom chums. My bosom friends keep me awake all night.
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.