Seal (6)
I believe the answer is:
signet
'seal' is the definition.
(I know that signet is a type of seal)
This is the entire clue.
(Other definitions for signet that I've seen before include "Tinges (anag) - seal" , "Official seal" , "Small seal - type of ring" , "Little seal" , "'Seal, on a ring say (6)'" .)