CHEATER Anyone who kills you. Ever. No matter that you left your keyboard for five minutes to take a piss (hmm long piss) they must have cheated to kill you. Only explanation.
CAMPER Often it's not tactful to call everyone a cheater, so this is the alternative. Phrases like "YOU FUCKING CAMPING FAGGOT" translate roughly to "Well done mate, good shot."
WHORE Someone who is not very nice. They probably just killed you with a glock despite your efforts with the para.
BIATCH Something to label the nearest person to you when you die. After all its not as if you would have ACTUALLY died normally. Someone MUST have got in your way, or be cheating or something.
RAPED Somtimes when you are outplayed (its inevitable, trust us) you may wish to confer your congratulations to your wily attacker. Such respects are payed by saying you were "raped". An example might be if a FUCKING CAMPING FAGGOT killed you from the tower near the CT respawn on seige. You didn't even see it coming, it was a deadly shot and a good move, so its nice to say politely "FUCK ME, I WAS RAPED!".
w00t! This has no real meaning, and is used primarily to baffle and amaze onlookers by confounding them. Be careful and don't fall for it!
WTF?! This is short for WHAT THE FUCK?. A useful acronym that is used quite often to inform others that you tentatively believe that you were a little unlucky to die in the way you did (i.e. you shot a guy twice with your AWP but he still managed to get 5 headshots with his TMP, kill you and live).
FUCK ME! A request for sexual gratification from another player.
OMG This stands for OH MY GOD. It is common to spurt this and as many other acronyms as available after each time you die, to let the other players know you are still around. Extra Blasphemy: OMFG - Oh My Fucking God
BS Short for BULL SHIT. Some of the more advanced players use this to explain to others that they might have been hard done by in the last round when the utter newbie knifed them to death in the lag.
GG Short for GOOD GAME and the only thing short enough to type quickly at the end of a map. Rest assured that if you are a quick enough typist other things are quite acceptable here, for example: "Good game my ARSE you fucking camping faggots" or the much more crytpic "OMG FFS! BS GG WTF?!? w00t! l337!"
FUK This basically is a term used to berate oneself for poor play. Typically said after getting knifed to death trying to hit a guy with your AUG.
FUCKING LAG This is typically a clever bluff to inform other players that you may be a little lagged. Thinking you are a bit lagged they may treat you with less attention and allow you to do better.
I OWN YOU A polite way of reminding someone that you killed them. Typically this is replied to with "FUCKING CAMPING WHORE" which means "Well done".
FUCK YOU I OWN YOU This is our favourite and can pretty much be used in ANY situation. For example, your mum asks "Can you please pass the salt?" to which you can simply reply "FUCK YOU I OWN YOU".
PARA WHORE Someone with a weird fascination for having sex with guns.
CAMPING SLUT Someone who kills unwary combatants from the sheltered confines of his tent. I recommend it.
JUMPING WHORE Those players that play with the config +pogostickuparse option turned on. Sadly these people have been misinformed, jumping around all over the place is not actually in the counter-terrorism manual under fighting techniques.
CHEATING BASTARD Its good to have an alias for this one, especially if you die a lot. Typically a cheating bastard is a really good player who gets a lot of kills. The best players are always cheating bastards.
YOU MOTHERFUCKING GOAT DICK SUCKER! This is quite an inventive and imaginative one, it is pretty much saying without much ado that you are not happy with something someone else did.
FUCKING TEAMS!!! A polite call to those players who are doing really well (the cheating bastards) to consider evening up the teams a little. Generally such polite suggestions are ignored and one must be a little more insistent and say something like "YOU FUCKING PISSFUCK WANKERS, EVEN UP THE FUCKING TEAMS!!!", which is more effective.
FFS Stands for For Fucks Sake. Usually when a very smart teammate shoots you with friendly fire on, or when teammates give you no backup