Never use an acronym unless you are sure of its meaning, because if you say the wrong thing to the wrong person.....
Try not to use chat acronyms in real life, especially in formal writing or conversation. Doing this could be embarrassing depending on who you're communicating with.
Chat Acronym Dictionary
121: one to one
ADN: any day now
ADR/addy: address
AFAIK: as far as I know
AFK: away from keyboard
A/S/L: age, sex, location (or just "ASL")
ASAP: as soon as possible
B4: before
B4N: bye for now
BBFD: big bad forum discussion
BBL: be back later
BF: boyfriend or best friend
BFF: best friends forever
BFN: bye for now
BG: big grin
BRB: be right back
BRT: be right there
BTA: but then again
BTW: by the way
C: see?
CID: crying in disgrace
CNP: continued [in my] next post
CP: chat post
CU: see you
CUL: see you later
CYA: see you (later)
CYO: see you online
DBAU: doing business as usual
DD, DH, DS, DW: dear daughter, dear husband, dear son, dear wife (often used on boards where you discuss personal things, but wish to keep private the names of your loved ones)
EIP: editing in progress
FTW: for the win or f*** the world
FUD: fear, uncertainty, and doubt
FWIW: for what it's worth
FYI: for your information
G2G or GTG: got to go
G: grin
GA: go ahead
GAL: get a life
GF: girlfriend
GFN: gone for now
GFY: go f*** yourself/good for you*
GG: gotta go/good game
GJ: good job
GL: good luck
GMBO: giggling my butt off*
GMTA: great minds think alike
GSOH: good sense of humor
GTFO: get the f*** out
GTG or G2G: got to go or get together
GYPO: get your pants off
H2G: have to go
HAGN: have a good night
HDOP: help delete online predators
HHIS: hanging head in shame
Homg: same as OMG
IAC: in any case
IANAL: I am not a lawyer (but)
IAWTC: I agree with this comment
IC: I see
IDC:I don't care
IDK: I don't know
IFSFWI: if the shoe fits, wear it!
IIRC: If I recall correctly
ILU: I love you
ILY: I love you
IMNECTHO: in my not-even-close-to-humble opinion*
IMNSHO: in my not so humble opinion
IMO: in my opinion; or "IMHO" - in my humble/honest opinion
IOW: in other words
IPN: I’m posting naked
IRL: in real life
IWSN: I want sex now
JC: just chilling
K: all right
KFY: kiss for you
KTHX: Okay, thanks.
JK: just kidding
JSUK: just so you know
KPC: keeping parents clueless
L8R: later
LAFFO: laughing out loud
LBR: loser beyond repair*
LD: later, dude
LDR: long distance relationship
LLTA: lots and lots of thunderous applause
LMIRL: let's meet in real life
LMAO: laughing my *** off
LMSO: laughing my socks off
LMFAO: laughing my f*** a** off
LOL: laughing out loud, lots of love
LQTS: laughing quietly to self
LTP: learn to play (L2P)
LTR: longterm relationship
LULAB: love you like a brother
LULAS: love you like a sister
MML: making me laugh
MMORPG: massively multiplayer online role playing game
MOOS: member(s) of the opposite sex
MOSS/MOTSS: member(s) of the same sex
M/F: male or female
N1: nice one
NALOPKT: not a lot of people know that
NE1: anyone
NFI: no f****** idea
NFW: no f****** way
NIFOC: naked in front of computer
NO1: no one
NSFW: not safe for work
NP: no Problem
NVM: nevermind
NM: not much, nothing much, never mind
OIC: ohh I see
OMG: oh my God, oh my goodness, oh my gosh
OMGBBQWTF: oh my God, Bar-b-q, What The F*** (surprise and confusion)*
OMFG: Oh my f*****g God
OLL: oh, Lordy, Lordy!*
OLL: online love
OMW: on my way
OTOH: on the other hand
OTW: on the way
P911: parent alert
PAL: parents are listening
PAW: parents are watching
PIR: parent in room
POS: parent over shoulder / Piece of S***
PLZ: please
PlzKThx: Please. ok? Thanks. (Thanks in advance)
PlzKThxNo-Re: Please, ok, Thanks, No-Read (sarcasm)
PL0x or PLOX: same as please
Pwn: to triumph (not actually an acronym, but rather a misspelling of own)
PDA: public display [of] affection
QFT: quoted for truth
RBA: right back at you (right back atcha)
RL: real life
RTFM: read the f*****g manual
RTFO: rock the f***** out
ROFL: rolling on floor laughing
ROTFLOL: rolling on the floor laughing out loud
ROFLMAO: rolling on the floor laughing my a** off
ROFLMAOSCOMN: rolling on the floor laughing my a** off spitting/spewing Coke out my nose*
RPG: role playing games
RP: roleplay
SA: something awful
SGXK: set a good example for the kiddies
SHID: slaps head in disgust
SLAP: sounds like a plan
SLGF: secondlife girlfriend
SO: significant other
SOMY: sick of me yet?
SorG: straight or gay
SOT: short of time
SUF: shut up fool
STFU: shut the **** up
STHU: shut the h*** up
TDTM: talk dirty to me
THX: thanks
TMI: too much information
TTFN: ta-ta for now
TTYL: talk to you later
TTLY: totally
TY: thank you
U: you (common); how are you?; or you do it!
UW: you’re welcome
WAYT: what are you thinking?
WB: welcome back/ write back
WDYT: what do you think
WFM: works for me
WIBNI: wouldn't it be nice if
WIP: work in progress
WTGP: want to go private?
WTG: way to go
WTF: what the ****, alternatively Where's The Food
WUIP: wind up in progress
WYCM: will you call me?
WYSIWYG: what you see is what you get
Y: why do you ask?
YM: young man
YMMV: your mileage may vary
YTMND: you're the man now, dog
YW: you're welcome
ZOMG: same as OMG
omG: Oh my GUY
CTM: certainly*
CBMY: too bad*
NQN: NOT QUITE NICE (all caps was used on purpose)*
LQTM: laughing quietly to myself
HRNSQ: Harlanesque (of or relating to Harlan)*
NHH: one who is Harlanesque*
WIT: What is this
*author favorites
**The authors apologize if any reader is offended by the meanings of any acronyms seen above.