Definition: (verb) to be an obsessive fan of someone or something (noun) an obsessive fan
Example: I stan Keanu Reeves. John Wick is the best movie ever.
“This is a @lizzo stan account.”
Though stan is usually positive these days, it didn't start out that way. The term originally came from the Eminem song "Stan," whose lyrics are a plea for Eminem's attention from a stalker-like fan, who says,
Dear Slim, I wrote you but still ain't callin'
I left my cell, my pager, and my home phone at the bottom
I sent two letters back in autumn, you must not-a got 'em
There probably was a problem at the post office or somethin'
When Eminem doesn't respond, he grows angry and sings, "I hope your conscience eats at you and you can't breathe without me."
Initially, stan was used as a noun. Now it's common as a verb, and though it's still obsessive, it's not as over-zealous as it was earlier, as can be seen in the above tweet posted by television writer and producer Shonda Rhimes. Like most slang, it continues to evolve.
It has also changed in that it is now used about things other than celebrities. For instance, I recently read an article on defector.com in which the author, Caitlin Schneider, writes joking reviews of U.S. flags. Commenting on Wyoming's state flag, she says, "In this house we stan the American bison, but we do not stan this flag. The placement of the seal within the bison is killing me."
I have to admit that while my feelings about bison are not quite as strong, I do feel the same way about this flag, pictured below. It's just weird.