1. A person who attempts to act badass behind their computer screens through their own keyboards. This definition is most commonly used by the populice that was tormented in upper-grade schooling and have no spine to speak of.
2. A person who throughly thrashes definition #1 using intelligence and wit only. This populice most commonly keeps to themselves until some fool comes along that needs to be slapped down properly, they do not go around looking to be badass, they just happen to have it come to them.
Def#2: instead of trying to be a keyboard gangster why not simply learn the definitions of the words you intend to use in everyday life, please vacate the premises before i make you feel as dumb as you look right now.
These people then blatantly ignore the people they have harassed the next day in person, pretending it didn't happen.
Person2: "What a keyboard gangster"