If you mean "dis"allow the flow, it's because electrons cannot travel easily between the atoms of the material.
Wood.
A conductor allows electricity to flow. An insulator does not.
Something or some material which is unable to allow currents to flow.
Because of freely moving of electrons in the material
a copper wire
a copper wire
a copper wire
A conductor - usually copper wire.
A material that electricity can conduct electricity.
An insulating material, also known as a dielectric, is a material that does not allow the flow of electricity through it due to its high resistance to electrical current.
Any conductor like copper or silver or aluminum
It prevents the flow of electricity since they do not have mobile electrons or mobile ions to allow the flow of electricity.