Expertise (5)
'expertise' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for skill that I've seen before include "Ability - dexterity" , "facility" , "Ability acquired by training" , "Talent" , "Expertise; art" .)
'expertise' is the definition.
(thesaurus)
This is all the clue.
(Other definitions for adeptness that I've seen before include "Deftness, adroitness" , "complete skill" .)