Conservative force : If a work done by force doesn't depend on the path but depends only on initial and final conditions, then the force is called conservative. Under the influence of conservative force the work done in a complete cycle is zero.
For example : Restoring force, central force, gravitational force etc.
Non-conservative force: If the work done by a force depends on the path then the force is called non-conservative. The work done in complete cycle is not zero.
For example : Viscous force, friction force, damping force etc.