mastery noun

ADJ. absolute, complete, total | gradual Children show gradual mastery of reading in the first years at school. | practical, technical He plays the violin with technical mastery, but no feeling.

VERB + MASTERY have The allied bombers had total mastery of the skies. | demonstrate, display, show He shows complete mastery of the instrument. | achieve, acquire, attain, gain

PREP. ~ of He acquired mastery of four languages. | ~ over The king had absolute mastery over the country.