also: そっす
godan verb (-su), intransitive verb
Archaic intransitive godan verb used especially for the death of nobles or high-ranking individuals. Not used in modern Japanese; replaced by 亡くなる or 死去する.
古文書には「公卿卒す」と記されている。
In old documents, it is written 'the court noble passed away'.
Archaic kanji spelling; the reading しゅっす is the standard historical reading.
Alternate archaic reading; less common than しゅっす.
The kanji 卒 means 'soldier' or 'to die', and the verb 卒す is an archaic form meaning 'to die', especially for nobility. The exact historical derivation is uncertain.