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Webster 1913 Edition

adv.

In a knavish manner; dishonestly; fraudulently.

Holland.

Mischievously; waggishly; roguishly.

“Knavishly witty.”

Gayton.

, na'vishly. Dishonestly; fraudulently.

Waggishly; mischievously.

knavishly ‎(comparative more knavishly, superlative most knavishly)

In a knavish manner.
- 2008 March 6, Nate Chinen, “A Night of ‘Warpaint,’ a New Set of Crowes”, in New York Times:
  Then he played hard to get, knavishly sidestepping the microphone.