a. 1. Inclined to play the master; domineering; imperious; arbitrary. Dryden. [ 1913 Webster ]
2. Having the skill or power of a master; indicating or expressing power or mastery. [ 1913 Webster ]
His masterful, pale face. Mrs. Browning. [ 1913 Webster ]
adv. In a masterful manner; imperiously. [ 1913 Webster ]
A lawless and rebellious man who held lands masterfully and in high contempt of the royal authority. Macaulay. [ 1913 Webster ]