blonde moment

American  

noun

Often Facetious.

1. a brief mental lapse, as of judgment or memory.

   I must be having a blonde moment.

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Etymology

Origin of blonde moment

First recorded in 1990–95; from the stereotype that blondes are not intelligent

Example Sentences

“Sometimes you hear someone say ‘Dumb blonde moment!’ or just, ‘Wow, I can’t believe I didn’t get that,’ you know, and they laugh it off,” Coleman said.

From Washington Post

"Having a legally blonde moment and I’m not mad about it," Sims captioned the snapshot, referencing Reese Witherspoon's character, Elle Woods, in the 2001 film.

From Fox News

When some tried to discourage the Oscar winner from creating more female-focused films, she had a Legally Blonde moment.

From Time