Dys- \Dys-\ An inseparable prefix, fr. the Greek ? hard, ill, and signifying ill, bad, hard, difficult, and the like; cf. the prefixes, Skr. dus-, Goth. tuz-, OHG. zur-, G. zer-, AS. to-, Icel. tor-, Ir. do-.

Source: Webster's Revised Unabridged Dictionary (1913)