Noun

(physics, uncountable, or, countable) The property of a body that resists any change to its uniform motion; equivalent to its mass.

(figuratively) In a person, unwillingness to take action.

* Carlyle

Men have immense irresolution and inertia .

* 2014 , Jacob Steinberg, " Wigan shock Manchester City in FA Cup again to reach semi-finals", The Guardian , 9 March 2014:

City had been woeful, their anger at their own inertia summed up when Samir Nasri received a booking for dissent, and they did not have a shot on target until the 66th minute.

(medicine) Lack of activity; sluggishness; said especially of the uterus, when, in labour, its contractions have nearly or wholly ceased.

Noun

(-)

The rubbing of one object or surface against another.

* {{quote-magazine, year=2013, month=July-August, author=(Henry Petroski)

, title= Geothermal Energy , volume=101, issue=4, magazine=(American Scientist) , passage=Energy has seldom been found where we need it when we want it. Ancient nomads, wishing to ward off the evening chill and enjoy a meal around a campfire, had to collect wood and then spend time and effort coaxing the heat of friction out from between sticks to kindle a flame.}}

Conflict, as between persons having dissimilar ideas or interests; clash.

(physics): A force that resists the relative motion or tendency to such motion of two bodies in contact.

* 1839 , (Denison Olmsted), A Compendium of Astronomy Page 95

Secondly, When a body is once in motion it will continue to move forever, unless something stops it. When a ball is struck on the surface of the earth, the friction of the earth and the resistance of the air soon stop its motion.