masterly UK /ˈmɑːstəli/US /ˈmæstɚli/adjective 2adverb 1forms 2 adjective2 •Executed in the manner of a master; showing competence and skill; masterful.Her years of experience enabled her to render a masterly performance. •(disapproving, no longer used) Like a master; arbitrary; domineering, imperious.Many times fear is a profitable and an active servant, if it do not dominere and grow masterlie. — 1653 adverb1 •(no longer used) In a masterful manner; competently, masterfully.At length the sound of a flute broke upon mine ear; it was not played masterly, but the tones were very sweet; and what is more correct, perhaps, they harmonized with my feelings. — 1818 formsmore masterly · most masterly