One who refuses to get their own FB account and instead uses their spouse of significant other's account. This allows them to truthfully deny having an account. This person uses the account to check up on family members and friends.
Sister: "Dad was on mom's FB account again! He grounded me because I cursed on FB."
Brother: "Yeah, he's such an Undercover FB User."
Someone who uses a/their computer typically for accessing the internet esp. social media, video chat, typing up documents, and stuff that has to do with work (if the person is a student or a businessman), and just surfing the net in general. In other words, the complete opposite of a HPCU Hardcore Personal Computer User
"I know I'm highly likely to be coming off as lame, but I really don't use my computer for gaming...that shit's boring! What can I say...I'm a CPCU (Casual Personal Computer User).
The user of a company named Apple which has the goal to rob all the money from their users which have fallen into their complex trap.
Also, apple devices are mostly used as a status in front of other people.
Apple users are often, but not limited to, called "applefags".
"Yo Joe, look at my new iPhone 12 Pro Max Plus in Gold Edition! It just cost me 3599$!!!!"
"Man, Jamie, you are such an apple user."
The original Dungeons & Dragons arcane class, roughly equivalent to the current (fourth edition) wizard class. At the beginning of a game, a magic-user would have only one spell (typically, sleep or magic missile), could have as little as one hit point, and couldn't wear any armor. A sucky character for the first several adventurers, and not likely to live very long.
Al-Kazak Elam, first level magic-user, enters the dungeon with his fellow adventurers.
Dungeon Master: You're attacked by a kobold (rolls dice). The kobold has initiative, attacks, and (rolls) does one point of damage to (rolls) Al-Kazak.