'antinephritic' originates from the combining form 'anti-' (Greek 'anti', meaning 'against') + 'nephritic' (from Greek 'nephros', meaning 'kidney', via New Latin/medical usage).

'nephros' (Greek) gave rise to New Latin/medical 'nephritis' (inflammation of the kidney) and the adjective 'nephritic'; the adjective 'antinephritic' was formed by adding the prefix 'anti-' to mean 'against nephritis' and entered English in medical usage.

Initially it denoted simply 'against nephritis' or 'preventing nephritis'; over time it has remained largely the same, used either descriptively (adjective) or to name agents (noun) that counteract kidney inflammation.