tinfoil
Americannoun
noun
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thin foil made of tin or an alloy of tin and lead
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thin foil made of aluminium; used for wrapping foodstuffs
Usage
What is a tinfoil hat? Tinfoil hat is a shorthand for saying someone believes in conspiracy theories, is paranoid, or is crazy more generally.
Etymology
Origin of tinfoil
First recorded in 1425–75, tinfoil is from the late Middle English word tynfoile. See tin, foil 2
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
He was a 25-year-old tinkering with self-tanners, but all the intrigue and action seemed to be around the lab next door, with its strange music, flashing lights and tinfoil covering the porthole.
From The Wall Street Journal ● Mar. 18, 2026
During Monday’s hearing, he complained that mainstream news media, including the Washington Post, had portrayed him and his allies “like we have a tinfoil hat on our heads.”
From Slate ● Dec. 19, 2025
So I went to my hair cutter and had him do it, with the tinfoil and everything.
From Los Angeles Times ● May 28, 2024
As a familiar feral atmosphere gripped Rodney Parade and the tinfoil replica FA Cup trophies glistened under floodlit skies, it felt like another shock was brewing in Newport.
From BBC ● Jan. 28, 2024
I lifted the tinfoil wrapper off, and a voice interrupted me.
From "Root Magic" by Eden Royce
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
