Sly is an adjective, meaning one of the following:
- Clever in practical matters.
- Hiding ones true intentions or goals.
Its synonyms are "cunning" and "roguish".
Sly is also a proper masculine name, short for Sylvester. It is the name of several famous persons:
- Sly Stone, American musician, frontman for Sly & the Family Stone
- Sylvester "Sly" Stallone, American actor.
- Sylvain Grenier, Canadian professional wrestler.
- William Sly, Elizabethan actor and colleague of William Shakespeare.
Sly is the title of an opera by Ermanno Wolf-Ferrari.
Sly is also the first name of the main protagonist in the games:
- Sly Cooper and the Thievius Raccoonus
- Band of Thieves
- Honor Among Thieves
