A spice very quietly eaten by noble (6)
I believe the answer is:
pepper
'a spice' is the definition.
(thesaurus)
'very quietly eaten by noble' is the wordplay.
'very quietly' becomes 'pp'.
'eaten by' is an insertion indicator.
'noble' becomes 'peer' (peer is a kind of noble).
'pp' going within 'peer' is 'PEPPER'.
(Other definitions for pepper that I've seen before include "A hot condiment, may be red" , "Condiment - discharge shot liberally" , "hit by gunshot" , "Dot" , "Hot spice" .)