MASTERLYa.
Formed or executed with superior skill; suitable to a master; most excellent; skillful; as a masterly design; a masterly performance; a masterly stroke of policy.
1. Imperious.
M`ASTERLYadv.
With the skill of a master.
Thou dost speak masterly.
"I think it very masterly written," in Swift, is improper or unusual.