1. 
[syn: craftily, cunningly, foxily, knavishly, slyly, trickily, artfully]
The Collaborative International Dictionary of English v.0.48:
Slyly \Sly"ly\, adv.
   In a sly manner; shrewdly; craftily.
   [1913 Webster]
         Honestly and slyly he it spent.          --Chaucer.
   [1913 Webster]
WordNet (r) 3.0 (2006):
slyly
    adv 1: in an artful manner; "he craftily arranged to be there
           when the decision was announced"; "had ever circumstances
           conspired so cunningly?" [syn: craftily, cunningly,
           foxily, knavishly, slyly, trickily, artfully]