The term haptosis 'non-consensual sexual touching' seems to derive from Greek απτω (hapto) 'to fasten, join; grasp, fasten onto; engage in, undertake'. LSJ also gives a gloss of 'to have intercourse with a woman' which occurs in Plato, Aristotle, and Ep. Cor. vii.1 (i.e., "it is good for a man not to touch a woman"). The ultimate etymology past Greek is obscure (Kretschmer sec. Chatraine, not in Pokorny). Only 268 ghits; seems like a newish neologism.

Perhaps related to haptic: http://wordsmith.org/board/showthreaded.pl?Cat=&Board=words&Number=148179