Synonyms to underhandedly

guilefully, 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, warily, wilily, at an angle, by proxy, circlewise, circuitously, deviately, deviously, digressively, divagationally, divergently, excursively, in behalf of, obliquely, on one side, round about, sideling, sidelong, sideways, sidewise, to one side, infamously, abominably, atrociously, awfully, basely, bestially, brutally, contemptibly, criminally, crookedly, despicably, detestably, discreditably, disgustingly, dishonestly, dishonorably, disreputably, dreadful, dreadfully, dubiously, egregiously, evasively, feloniously, fishily, flagrantly, foully, fulsomely, grossly, horribly, horridly, ignominiously, ingloriously, knavishly, loathsom