slyly

from 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}]

from 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]