avadyá- ‛vice’ appears already in the Ṛgveda and is attested in the simplex and in compounds throughout the history of Sanskrit and Middle Indic. As I have argued in my 2012 paper published in Japanese in the Journal of Indian and Buddhist Studies (vol. 60,2), by regular sound change, Sanskrit avadyá- corresponds to Pali avajja-, while Sanskrit varjya- ‛(that which is) to be avoided = vice, sin’ corresponds to Pali vajja- ‘vice’. In this talk I will present a detailed examin¬ation and comprehensive account of avadyá- and the contexts in which this word is used in Vedic, later Sanskrit, and Middle Indic. Already in Vedic, avadyá- has undergone some degree of lexicalization, a claim which is supported by Pāṇini’s an-alysis of the word. Due to regular processes of sound change in Middle Indic, the word became prone to confusion, and this led to an interesting reanalysis in Pali and a surprising Chinese translation that is found in the Ratnarāśisūtra.