truther

noun

someone that asserts that the 2001 terror attacks are at the center of a conspiracy
someone who is convinced that a powerful conspiracy is actively hiding the real facts regarding a significant topic or event from the general public

Pronunciation: /ˈtɹuθɚ/ / /ˈtɹuːθə/

Etymology: From truth + -er (occupational suffix) or + -er (“supporter”). For sense 2, directly from name of the 9/11 Truth movement.

Someone who tells the truth.
“A liar can't begin to start the riots a truther can.”
Someone who believes that the US government was responsible for the 9/11 attacks.
“[signed] 9/11 Truther”
“Therefore, virtually every press release or statement about 9/11 should include a reference to the poll to show people that many Americans are 9/11 truthers who scoff at the 9/11 Commission as a fraud and that demand a real 9/11 investigation.”
A conspiracy theorist who does not believe the accepted story about some significant event, fact, etc.
“For instance, "truthers" who believe in a US government conspiracy to destroy the pentagon”
“Rather, believers of this conspiracy theory (known as Sandy Hook “truthers”) propose that the entire event might have been staged by Homeland Security and FEMA”
An advocate, especially for a headcanon.