Question

What are dielectrics

Answer 1

Dielectric, insulating material or a very poor conductor of electric current. When dielectrics are placed in an electric field, practically no current flows in them because, unlike metals, they have no loosely bound, or free, electrons that may drift through the material. Instead, electric polarization occurs.

Answer 2

dielectrics are a substance or you can also say it as a medium which doesn't allows electricity to pass through them. They can also be called as insulators.
Hope it's correct.