masterly

masterly is an   Adverb

Definition:

[1] Suitable to, or characteristic of, a master; indicating thorough knowledge or superior skill and power; showing a master`s hand; as, a masterly design; a masterly performance; a masterly policy. "A wise and masterly inactivity." Sir J. Mackintosh.

[2] Imperious; domineering; arbitrary.

Synonyms: