Source : Webster's Revised Unabridged Dictionary (1913)

Impertinently \Im*per"ti*nent*ly\, adv.
   In an impertinent manner. ``Not to betray myself
   impertinently.'' --B. Jonson.

Source : WordNet®

impertinently
     adv : in an impudent or impertinent manner; "a lean, swarthy
           fellow was peering through the window, grinning
           impudently" [syn: {saucily}, {pertly}, {freshly}, {impudently}]