proficient vs proficiency

proficient is not a noun while proficiency is a noun.

Word	Noun	Adjective	Verb	Adverb
proficient	No	Yes	No	No
proficiency	Yes	No	No	No

proficient (noun)	proficiency (noun)
	the quality of having great facility and competence
	skillfulness in the command of fundamentals deriving from practice and familiarity

proficient (adjective)	proficiency (adjective)
of or relating to technique or proficiency in a practical skill
having or showing knowledge and skill and aptitude