tinfoil hat

noun

plural tinfoil hats

figurative

: an irrational or paranoid belief especially in a conspiracy theory

This country has long cuddled conspiracies close to its heart. We are a nation that loves tinfoil hats.

—Marshall Kilduff

—often used in phrases like wear a tinfoil hat or put one's tinfoil hat on to suggest that the wearer holds such beliefs

… and suddenly you're the paranoid one wearing a tinfoil hat.

—Niall McCrea

It used to be only the people wearing tinfoil hats that were worried about satellites flying above us all the time.

—Michael Ho

… I'm going to put my tinfoil hat back on now and hopefully see you next week unless the aliens get me.

—Charles Duhigg

—sometimes used before another noun

tinfoil hat conspiracies

Note to the tinfoil hat crowd: That was a joke, folks.

—Ted Diadiun

Word History

Etymology

from the notion that such a hat would protect the wearer from invisible assaults on the brain by electromagnetic radiation, mind control, etc.

First Known Use

1982, in the meaning defined above