1903, Philip P. Wells, Bible Stories and Religious Classics:
Then the ministers and two Christian men, Theodorus and Rufinus, wrote their martyrdom and laid it subtlely among the stones.
2006, Emile Zola, Nana, The Miller's Daughter, Captain Burle, Death of Olivier Becaille:
She walked about for a moment or two in order the more thoroughly to show off her paces, and as she walked she smiled subtlely, closed her eyes demurely and managed her skirts with great dexterity.
1890, Mrs. E. D. E. N. Southworth, For Woman's Love:
But you must insinuate the idea very slowly and subtlely.
1892, Annie S. Swan, The Guinea Stamp:
Never was man so subtlely flattered, so tempted.
1911 & 1914, Thomas Common (translator); Oscar Levy (editor), Friedrich Nietzsche[:] Thus Spake Zarathustra[.] A Book for All and None[.], 2nd & 3rd edition, The Macmillan Company, translation of original by Friedrich Nietzsche, page 196:
The door sprang subtlely open unto me, and said "Go!"