In physics terms the difference between relativistic and graphino

is that relativistic is at, or near the speed of light while graphino is a massless charged relativistic quasiparticle that arises from the low-energy excitations in a 2D graphene sheet interacting with an electromagnetic field.

As an adjective relativistic

is of, or relating to relativity.

As a noun graphino is

a massless charged relativistic quasiparticle that arises from the low-energy excitations in a 2D graphene sheet interacting with an electromagnetic field.