say it: pruh-FISH-uhn-see
proficiency is a noun meaning "the quality of having great facility and competence". It carries 2 recorded senses.
the quality of having great facility and competence
skillfulness in the command of fundamentals deriving from practice and familiarity
“practice greatly improves proficiency”
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for proficiency come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.