siu4

hong kong internet slang for "笑死", meaning "laughing to death"
"siu4" and "笑死" shares the same sound but has different tones

me: *sends a meme*
friend: siu4

.gun

abbreiviation for "點跟" which roughly translates to "How am I supposed to follow?"
The term used between Hong Kong cyclists.
Usually used to praise one's speed on the bike.

Me: What's your FTP?
New friend: 10 watts/kg
Me: .gun

2035

A term for "permanent ban" in the game Warframe.
Players who are permanently banned will be prompted with the following message on logging into the game
"Account suspended until Jan 01, 2035 due to End User License Agreement Violation"

He got so salty from being banned from the clan he went nutcase and got himself 2035'd from the game.