expression, godan verb (-ku)
resign from a public position; leave government service
Rare, literary expression. Literally 'untie the ribbon (of the official seal)', used figuratively for resigning from an official post. The literal meaning is not used in modern Japanese.
See also: 綬を結ぶ
彼は長年の勤めを終え、綬を解く決意を固めた。
After many years of service, he resolved to resign from his public position.