Someone who constantly looks for an excuse to use their knife to accomplish trivial tasks that could easily be solved using you bare hands/teeth.

Someone who is possessed by clout chasing. The original human is now gone and a demonic entity that feeds on clout is all that is left. An empty shell with no control of their actions, forced to blindly react to situations they think will bring them attention.

A person who regularly brings a knife or other cutting tool to their school/workplace in a vain attempt to look cool. They will frequently play with the knife and use it on every inanimate object in sight.
See also lighter fag

A person who plays Modern Warfare 2 and runs around stabbing everyone with a knife