Having or showing the knowledge or skill of a master. See Usage Note at masterful.(adjective)
With the skill of a master.(adverb)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "masterly" in a sentence
"Christ in masterly fashion drew a distinction between God and emperor while at the same time decreeing obedience to both God and emperor  – a fact that did not prevent the imperial procurator's condemnation of Christ to death on the cross."
"‘With pleasure,’ said I, and playing another measure in masterly fashion, sang thereto these couplets,"
"The painters, hearing these words, applied themselves with all diligence to do what he required of them and wrought it out in masterly style; and when they had made an end of the work, they showed it to the Wazir who, seeing his so-called dream set forth as it was280 was pleased and thanked them and rewarded them munificently."