Can be confused: masterful, masterly
(see usage note at the current entry).
1. peremptory. 3. consummate, supreme; adept, expert, skilled, skillful, matchless.
At an earlier time, both masterful and masterly had two senses: “having a commanding or domineering nature or manner” and “possessing the skill of a master.” The earliest sense of masterly, “having a commanding nature,” has been obsolete since the 18th century. Masterful continues to be used in all varieties of speech and writing in both senses, despite the protests of some who prefer that masterful be restricted to the sense “dominating or imperious”: The envoy's masterful behavior irritated the citizens. Few painters have produced so many masterful (or masterly) portraits.