1. Cunning or crafty.
2. Of or resembling a fox.
His olive complexion surrounded a vulpine smile whenever he looked in the direction of the defendant.
-- Jeffrey R. Ryan, A Volcano Heard Afar
McCone was aware of what was happening, and his leaning posture became more and more vulpine.Vulpine derives from the Latin word for "fox," vulpinus.
-- Stephen King, Richard Bachman, The Running Man