Someone who is stupid and/or silly. Geez, he keeps pulling on a door that's clearly marked "push"—what a feather brain.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
n. a stupid person. (Also a rude term of address.) Hey, feather brain. Wake up and get busy!
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.