The Collaborative International Dictionary
Guileful \Guile"ful\, a. Full of guile; characterized by cunning, deceit, or treachery; guilty. -- Guile"ful*ly, adv. -- Guile"ful*ness, n.
Wiktionary
adv. In a guileful manner.
Usage examples of "guilefully".
Then sounded footsteps along the avenue, and my fear whispered that they were not those of Bristol but of one who had murdered him, and who came guilefully, to murder me!
He wove warily to the right, clashed aside a couple of probing strokes that were meant only to mislead, and essayed a few of his own no less guilefully.
The women, girls just reaching maturity and matrons mated for many years, were more modestly and guilefully dressed in garments which would be put away after the night's revels to serve another year, when another Spring Night came and the polar sluices were again thrown open to send the waters of the melting ice-cap flooding through the ancient rock-hewn channels to bring new life and new beauty to half of Mur.