late 14c., "urge on, incite" (implied in abetting), from Old French abeter "to bait, to harass with dogs," literally "to cause to bite," from a- "to" (see ad-) + beter "to bait." This verb is probably from Frankish or some other Germanic source (perhaps Low Franconian betan "incite," or Old Norse beita "cause to bite"); ultimately from Proto-Germanic *baitjan, from PIE root *bheid- "to split," with derivatives in Germanic referring to biting. Sense of "encourage by aid or approval" is from 1779. Related: Abetted; abetting.