What opposes the sliding motion of two

surfaces that are in contact.

Friction: A force that opposes the motion of objects that touch as they move past each other. Friction acts at the surface where objects are in contact.

Explanation:

The force that acts against your pushing force is called friction. is a force that resists the motion between two surfaces in contact. When you try to slide two surfaces across each other, the force of friction resists the sliding motion.