tinfoil hat

plural tinfoil hats · alternative tin foil hat · alternative tin-foil hat

1. A piece of headgear made from one or more sheets of tin foil, aluminium foil, or other similar material; especially when worn in the belief that it shields the brain from electromagnetic fields or against mind control or mind reading.

   To prevent them from reading his mind, he wore a tinfoil hat at all times.

   2001, Eoin Colfer, Artemis Fowl, page 42

   4 more examples

   Jeanne Due's ingenuity has sent the most remarkable of hats, this being the now notorious tinfoil hat, pictured elsewhere. The strangest part about this weird creation, however, is the fact that it is not unbecoming, but quite wearable.

   1916, Roger W Allen, editor, Millinery Trade Review, volume 41, page 27

   I mean, as much as any daughter, I want to make sure my mother is headed for happiness and not heartbreak, but Connie's taken it up a notch, to tinfoil-hat territory.

   2008, Libby Sternberg, Recovering Dad, page 27

   It’s true that Team Trump, and its cowering minions in Congress, eventually parted ways with Powell as her professional demeanor gradually slipped to reveal her tinfoil hat.

   2021 March 23, David Von Drehle, “Sidney Powell does an about-face on her Stop the Steal claims”, in Washington Post, →ISSN

   Teachers in Russia have been fooled into posing for photos wearing tinfoil hats by a prankster who claimed they would protect them from a Nato plot. The teachers in the Voronezh region all received messages purporting to be from President Putin's ruling party urging them to make "helmets of the Fatherland" [i.e., decorated with the Russian flag]. Vladislav Bokhan, an exiled Belarusian blogger who opposes the Kremlin wrote that the tin-foil hats would protect against Nato satellites that were trying to "irradiate the Russian people physically and biologically". He told the teachers to provide photos and videos to prove that they had complied.

   2024 November 12, Richard Lloyd Parry, “Tin-foil hat brigade tricked into believing Nato space-ray plot”, in The Times, London: News UK, →ISSN, →OCLC

   Synonyms: TFH

2. derogatorymetonymicallyA conspiracy theorist.