Conductivity
Conductivity is a physical property of a material that describes how resistant a material is to the flow of electrical current through it.
A conductive material will allow the flow of current (they have a low resistance/ resistivity). Examples include metals and graphite, which both have free electrons that can flow freely within the material.
A non-conductive material will impose resistance to flowing electrons. Collisions between atoms and electrons disrupt the current by dissipating some energy as heat. This is why circuits and electrical devices can become hot after operating for a long time.
Figure 1 - Electrons traveling through a wire made of a conductor and an insulator.