From Biology-Online Dictionary | Biology-Online Dictionary


1. Dexterous in performing an action, so as to escape notice; nimble; skillful; cautious; shrewd; knowing; in a good sense. Be ye sly as serpents, and simple as doves. (Wyclif (Matt. X. 16)) Whom graver age And long experience hath made wise and sly. (Fairfax)

2. Artfully cunning; secretly mischievous; wily. For my sly wiles and subtle craftiness, The litle of the kingdom I possess. (Spenser)

3. Done with, and marked by, artful and dexterous secrecy; subtle; as, a sly trick. Envy works in a sly and imperceptible manner. (I. Watts)

4. Light or delicate; slight; thin. By the sly, or On the sly, in a sly or secret manner. Gazed on Hetty's charms by the sly. .

(Science: zoology) Sly goose, the common sheldrake; so named from its craftiness.

Synonym: Cunning, crafty, subtile, wily. See Cunning.

Origin: OE. Sli, slegh, sleih, Icel slgr, for slgr; akin to Sw. Slug, Dan. Slu, LG. Slou, G. Schlau; probably to E. Slay, v.t.; cf. G. Verschlagen sly. See Slay, and cf. Sleight.