An action that is unintelligent, forgetful, strange, or foolish. The use of "blond" comes from the stereotype that people with blond hair are not as smart. For that reason, it can be considered somewhat derogatory. I thought Mom knew Joe's phone number, but she's having a blond moment and can't remember it either.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
n. a lapse in thinking, something like a senior moment. Sorry. I was having a blond moment. And that’s hard for a redhead.
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.