Official stamp (6)
I believe the answer is:
signet
'official stamp' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for signet that I've seen before include "Tinges (anag) - seal" , "Small seal sounds like a young swan" , "Kind of ring with seal" , "Tuft of hanging threads" , "Ingest (anag)" .)