Question

Whats the difference between bad conductors , insulators and dielectric

Answer 1

A lot of things but the most important is that they conduct different type of energy

Answer 2

insulators does not allow flow of electric charges at all.
bad conductors are those which can conduct electricity but offers more opposition (resistence) to the flow of current compared to the flow of current in a good conductor.
all dielectrics are insulators, but all insulators are not dielectric.

hope this help