'Expertness' definitions:

Definition of 'expertness'

From: WordNet
noun
Skillfulness by virtue of possessing special knowledge [syn: expertness, expertise]

Definition of 'Expertness'

From: GCIDE
  • Expertness \Ex*pert"ness\, n. Skill derived from practice; readiness; as, expertness in seamanship, or in reasoning.
  • Syn: Facility; readiness; dexterity; adroitness; skill. See Facility. [1913 Webster]