Friction (noun)

1. The force that opposes motion between two objects in contact.
2. A state of conflict or opposition between people or groups.
3. A feeling of discomfort or resentment arising from opposing views or interests.
4. A resistance to smooth or easy movement or operation.
5. The physical force that opposes motion between two surfaces that are in contact.

Origin:

Late middle english: from latin frictio(n-), from frangere "to rub".

Examples:

1. The friction between the tires and the road affects the speed of the car.
2. The friction between the two countries has escalated into a full-blown conflict.
3. There was some friction between the team members over who would lead the project.
4. The friction in the gears was causing the machine to operate inefficiently.
5. The friction between the two objects made it difficult to move them.