sly

[ slahy ]
/ slaɪ /
SEE SYNONYMS FOR sly ON THESAURUS.COM

adjective, sly·er, sly·est.

cunning or wily: sly as a fox.
stealthy, insidious, or secret.
playfully artful, mischievous, or roguish: sly humor.

Idioms for sly

    on the sly, secretly; furtively: a tryst on the sly.

Origin of sly

1150–1200; Middle English sly, sley, from Old Norse slœgr “sly, cunning” (originally “able to strike, able to slay”); see slay

OTHER WORDS FROM sly

Words nearby sly

slut, slut-shame, slutch, sluter, slutty, sly, sly grog, sly-grog, slyboots, slyly, slype

Words related to on the sly

covert, furtive, hush-hush, unauthorized, clandestine, hidden, experimental, private, quietly, clandestinely, surreptitiously, covertly, privately, personally, furtively, stealthily, secretly, revolutionary, alternative, avant-garde

British Dictionary definitions for on the sly

sly
/ (slaɪ) /

adjective slyer, slyest, slier or sliest

crafty; artful a sly dodge
insidious; furtive a sly manner
playfully mischievous; roguish sly humour

noun

on the sly in a secretive manner

Derived forms of sly

slyly or slily, adverb slyness, noun

Word Origin for sly

C12: from Old Norse slǣgr clever, literally: able to strike, from slā to slay

Idioms and Phrases with on the sly (1 of 2)

on the sly

Furtively, secretly, as in She's always eating cookies on the sly. The adjective sly, which means “cunning” or “crafty,” is here used as a noun. [c. 1800]

Idioms and Phrases with on the sly (2 of 2)

sly

see on the sly.