friction

About 9.80 uses per million words.

Meaning

noun The rubbing of one object or surface against another.
noun A force that resists the relative motion or tendency to such motion of two bodies in contact.
noun A massage of the body to restore circulation.
noun Conflict, as between persons having dissimilar ideas or interests; clash.
noun Any obstacle or hindrance that makes a system less convenient or desirable to use.
Users have reported friction from having to enter their passwords many times a day.
noun Conflict during the Second Sino-Japanese War, as between the Communists and non-hanjian Kuomintang forces.