Archaic term for the ring finger; in modern Japanese, 薬指 is used instead. The word 名無し指 literally means 'nameless finger'.
See also: 薬指
The notation '名無し指' can be seen in old documents.
In the past, the ring finger was sometimes called '名無し指'.
Compound of 名無し (nameless) and 指 (finger). The exact historical derivation is uncertain, but the term likely arose from a taboo or avoidance of naming the finger directly.