expertness

English

From expert +‎ -ness.

expertness (usually uncountable, plural expertnesses)

The state of being expert.
Proficiency or skill.
- 1861, E. J. Guerin, Mountain Charley, page 22:
  I had […] armed myself with a revolver, in the use of which I finally reached a certain degree of expertness from frequent practice.
- 1902, William James, The Varieties of Religious Experience: A Study in Human Nature […] , New York, N.Y.; London: Longmans, Green, and Co. […], →OCLC, page 347:
  Not only must she receive unheard-of personal favors and spiritual graces from her Saviour, but she must immediately write about them and exploiter them professionally, and use her expertness to give instruction to those less privileged.

state of being expert

skill or proficiency