The state or quality of being adept or skillful.(noun)
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Use "skillfulness" in a sentence
"On the afternoon of April 9, 1865, at Appomattox Court House, Grant once again demonstrated the clarity of his thought and the skillfulness of his writing when he crafted surrender terms on the spot."
"This week's question comes from A.L.: How would Sid deal with lack of skillfulness when he blunders or makes a mistake?"
"This is because the skillfulness or experience of Iran's rulers should not be underestimated, as they are of the utmost cunning in the art of politics and trade-offs."