c6

stands for cybersex

Dude_1: let's c6!
Dude_2: c6?
Dude_1: k!

gifv

verb, imperative - A misspelling of the imperative "give" of the verb "to give" that is now an actual word commonly used in online games like mmorpgs. The word was probably coined by a rude guy unreasonably demanding people to give him stuff and typing this out very messily. People now use this word mockingly when posing demands.

Deathkillmurder: "m8s look at this uber bow I won in lotto!"
Fotmscout: "gifv bow!!11"
Gimpmanceralt: "wow, that's a nice piece of kit. I'll give you 10 plat for it"
Fotmscout; "gifv!11!!"
Deathkillmurder: "lol"

OR

Husband: "gifv dinner"

naab

The word "nààb" (and later on "naab") is derived from the word n00b meaning newb, newbie or beginner in internet slang.
Etymology: on azerty keyboards the "à" is on the same key as the "0": shift+"à" gives "0".
In the heat of a squabble people sometimes miss their shift key and end up typing nààb instead of n00b. Of course these people are so l33t that there typos become new words.

n00blet: "omg I emptied an entire mag in his face!"
l33tard: "nààb!"