One who accepts an argument or philosophy wholeheartedly and blindly.

The term is in reference to the religious cult led by Jim Jones, who committed mass suicide by drinking Kool-Aid laced with Valium and cyanide.
You'll never convince Mike not to buy that MacBook even though he just got a G4, he's such a kool-aid drinker.
by WhitneySir August 21, 2006
Someone who believes what they are told without thinking for themselves.

Sometimes used by aficionados of the 1911 handgun ("Colt .45") to describe fans of the Glock (or other polymer framed) handguns - possibly a reference to the nickname "tupperware gun" and the typical serving of Kool-Aid in plastic pitchers.

In more recent use it may also be applied to folks who think that any negative term or euphemism applied to President Obama or his acolytes automatically means the user is a racist.

The suggestion that the term applies only to a stereotype of African-Americans implies that no Caucasians drink Kook-Aid, an obvious fallacy and an indication of a significant pre-existing bias on the part of the writer, or a blatant attempt to suppress freedom of speech on the part of opponents.

From the followers of Jim Jones in Guyana who committed suicide by drinking poisoned Kool Aid.
The Kool Aid drinkers are buying this stock because their broker recommended it.

A Glock? What are you, a Kool Aid drinker?
by SikLikeDat August 27, 2009
Derived from the 60's drug culture when hippies would drop acid in their Kool Aid. A Liberal who is delusional in their beliefs.
If you believe the Federal government blew-up the World Trade Center, you're a Kool Aid Drinker. "We won't be truly free until all drugs are legal."
by Quandar June 17, 2006
Anyone who thinks politicians aren’t corrupt and the mainstream media is honest.
~ “Boy those deep state rhino politician whores Brian Kemp and Brad Raffensperger really sold out.”
~ “But there is no deep state - Wikipedia says so.”
~ Sigh Kool-aid drinker ⬆️
by Neurotica70 December 22, 2020
To act and or be stupid.
Gregg "Dude I'm crazy cool!"

Zach "No your a dumb ass Kool-Aid Drinker!"
by Zach Madigan March 6, 2008
A Kool Aid Drinker is a chick that loves to suck the dicks of men on their periods.
Suzy: Lizzy just came out of the restroom with Bill and now her mouth is all red.

Eddy: Lizzy must be a Kool Aid Drinker.

Suzy: What does that mean?

Eddy: Bill is having his man period.
by Skorpious July 17, 2020
A Kool Aid Drinker is a chick that loves to suck the dicks of men on their periods.
Suzy: Lizzy just came out of the restroom with Bill and now her mouth is all red.

Eddy: Lizzy must be a Kool Aid Drinker.

Suzy: What does that mean?

Eddy: Bill is having his man period.
by Skorpious July 17, 2020