What do you understand by the resistance of a conductor?

Suppose you and your friend is driving on different roads. Your road has patches and bumpers, while your friends road is a super highway. So, both of you are experiencing your drive in different manner. Yours will be rough while yours friend will be smooth. Now, the road is a conductor of vehicles. The patches and bumpers are resistance of the conductor. The more patches, the more resistance.

the conductors which can hold a certain capacity of current if exeeded it
melts 

Resistance is defined as the opposition to the flow of electrical current through a conductor. It's important to point out that conductivity and resistivity (the property that determines final resistance) are inversely proportional.

The electrical resistance of an electrical conductor is a measure of the difficulty to pass an electric circuit through that conductor.  The SI unit of electrical resistance is the ohm (Ω).

The resistance (R) of an object is defined as the ratio of voltage across it (V) to current through it (I), while the conductance (G) is the inverse: