adjective, sly·er, sly·est.
Origin of sly
Examples from the Web for slyness
He appeared to be somewhat excited, and went about his operations with an air at once of slyness and of mystery.The Lonely Island|R.M. Ballantyne
The sharp-faced fox is a very epitome of cunning, and his name is a by-word for slyness.Heads and Tales|Various
She had read him and was openly rejoicing in what she thought his slyness.The Call of the Blood|Robert Smythe Hichens
When the Crow was too lazy to search for food, she would resort to slyness.Verotchka's Tales|Mamin Siberiak
The slyness and its sisterly innocence lit up our eyes, and our hearts laughed.The Adventures of Harry Richmond, Complete|George Meredith
adjective slyer, slyest, slier or sliest
Word Origin for sly
c.1200, "skillful, clever, dexterous," from Old Norse sloegr "cunning, crafty, sly," from Proto-Germanic *slogis (cf. Low German slu "cunning, sly," German schlau), probably from base *slak- "to strike, hit" (see slay (v.)), with an original notion of "able to hit." Cf. German verschlagen "cunning, crafty, sly," schlagfertig "quick-witted," literally "strike-ready," from schlagen "to strike." A non-pejorative use of the word lingered in northern English dialect until 20c. On the sly "in secret" is recorded from 1812. Sly-boots "a seeming Silly, but subtil Fellow" is in the 1700 "Dictionary of the Canting Crew."
see on the sly.