People have wanted this for a while so I'll just start with the ones I know and I'll keep this post updated as people comment more of them
Commonly Used AcronymsRVS - Random Voting Stage
LyLo - Lynch Or Lose (Correctly [Lynch Scum Or Lose])
MyLo - Mislynch And Lose
FoS - Finger of suspicion
OMGUS - Oh my god you suck
VT - Vanilla Townie
PR - Power Role
WIFOM - Wine in front of me (this is what this causes me to think but the mafia might want me to think this)
Quickhammer - Voting for someone at L-1 who you were not voting for, to end the day for some reason (often to win as scum, or to stop discussion)
SK - Serial Killer
NK - Night Kill (Rarely No Kill based on context)
QH - Quickhammer
WW - Werewolf (on f.DS these are common only if there is multiple factions)
Commonly Used TermsBus -Building a case on your teammates and often voting for your teammates as scum
Sheep - to vote or argue without adding content of your own. (in reference to sheeplike (unoriginal) thinking.)
Tunnel: to develop tunnel vision on a player and see anything they do as scummy
ObvX - obviously X (e.g. obvtown = obviously town)
Breadcrumb - Leaving a hint at what your role is (or to set up a fakeclaim) in a post
Claim - to announce all of or parts of ones role
Massclaim - Everyone claiming their role in an order, normally to try and catch scum in a lie
F.DS SpecificDerphammer - Quickhammering as town, on town in a situation that doesn't benefit town
PINL - Promise I'm Not Lying
Twinclaim - the fact that you know another player in real life; and also deriving information from that fact. - First instance is Jo/Glooble in MIV
Pulling/Doing an eHunt - drunk posting often in a hilarious way. See MVI
DAMA - Drunk ask me anything, see Pulling/Doing an eHunt.
Pulling a Bozzball - Lurking oneself out of a game, from either faction. Generally caused by an apathetic attitude towards the game rather than a planned (or even unplanned!) strategy
Kickball - See Pulling/Doing an eHunt
No Lunch - Started as a phone typo by Axxle in BM3, turned into a joke by the mod and players of that game, means no lynch but tends to result in hungry mafia players.
S.H.D - Stop Halt Desist.
The "Morgrim Defense" - In his first game here (M2) Morgrim self hammered, since then he has raised his meta as someone who is always just a bit crazy and always seems super scummy. The Morgrim defense is that crazy Morgrim is town Morgrim. This forum has not yet seen scum Morgrim.
Pulling an Insomniac - Depending on context either, having the right lynch and talking yourself out of it and into a town lynch, or as an IC voting for someone you think as town in an attempt to catch the hammer...in a game where mafia have day chat.
Mom Salon - Refers to player Mcmcsalot, comes from a phone autocorrect in ZMIX.
Fuzzy - Refers to Eevee