An acronym for internet tough guy. An internet tough guy is a person usually male, about 35 years old living in his mothers basement on the internet that frequently makes threats about how much of a bad ass they are and makes claims of how much they've accomplished. The common internet tough guy will frequently say things like "STFU Noob", "Go fuck your mother, "your a fucking faggot", and so on. They'll also threaten with things like "I'll beat your ass", and "tell me where you live because i'll beat your ass there"
Actual youtube reply I got from an ITG
"ur a fukin fag half of the world smokes cocaine n ur pussy ass doesnt realize how much safer n better it is then alcohol and other shit so y dnt u jus stick to sniffing glue u fukin pussy ass faggot"