sly /ˈslaɪ/
  (a.)狡猾的,詭密的,淘氣的,偷偷摸摸的
  Sly a. [Compar. Slier or Slyer; superl. Sliest or Slyest.]
  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. [Obs.]
  By the sly, or On the sly, in a sly or secret manner. [Colloq.] “Gazed on Hetty's charms by the sly.” --G. Eliot.
  Sly goose Zool., the common sheldrake; -- so named from its craftiness.
  Syn: -- Cunning; crafty; subtile; wily. See Cunning.
  Sly, adv. Slyly. [Obs. or Poetic]
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  sly
       adj : marked by skill in deception; "cunning men often pass for
             wise"; "deep political machinations"; "a foxy scheme";
             "a slick evasive answer"; "sly as a fox"; "tricky Dik";
             "a wily old attorney" [syn: crafty, cunning, dodgy,
              foxy, guileful, knavish, slick, tricksy, tricky,
              wily]
       [also: slyest, slyer, sliest, slier]