List of guilefully synonyms and guilefully related words.
artfully, astutely, cagily, cannily, cleverly, cunningly, deceitfully, foxily, fraudulently, furtively, indirectly, insidiously, knowingly, on the sly, shiftily, shrewdly, slick, slyly, smoothly, subtilely, subtlely, surreptitiously, treacherously, trickily, underhandedly, warily, wilily