The 'rui' is the part of an old cap's tie that hangs down below the chin.
Tips
history
緌 is not used in modern Chinese. It is a classical word for the dangling tail of a hat-string, and by image the drooping feeler-mouth of a cicada, famous from the 《诗经》 hat imagery. The silk radical 糸 marks the cord; 委 supplies the sound.
register
Archaic and literary. You will meet 緌 only in classical text and etymology notes, never in modern speech or writing.
