sly

Sly is an English adjective describing a cunning, stealthy, or deceitful manner or appearance. It can refer to behavior, expressions, or tactics that are artfully clever and often intended to mislead or surprise. The term can carry a playful or mischievous nuance but can also imply disapproval when used of someone who uses cleverness to manipulate others. The adverb form is slyly, and the noun slyness exists to denote the quality itself.

Etymology and sense development: The word originates in Old English and has cognates in other Germanic languages. Its core sense—craftiness or stealth—appears in Middle English and has persisted into modern usage. The nuance ranges from lighthearted mischief to more pointed accusation, depending on context.

Usage and idioms: Sly is commonly found in phrases such as sly grin, sly smile, sly remark, or sly plan. The expression “sly as a fox” reflects a long-standing cultural association between cunning and foxes, a motif found in literature and folklore across cultures.

Cultural references and names: Beyond descriptive use, sly functions as a nickname or stage name. Notable individuals associated with the term include Sly Stone (Sylvester Stewart), frontman of Sly and the Family Stone, and the actor Sylvester Stallone, frequently referred to as Sly. In fiction and games, Sly Cooper is a well-known stealthy raccoon thief and the protagonist of a video game series.

See also: cunning, trickery, slyness, sly grin.