Cerumen (6)
I believe the answer is:
earwax
'cerumen' is the definition.
(synonyms)
This is all the clue.
(Other definitions for earwax that I've seen before include "Shell-like secretion" , "Waxy secretion impairing hearing" , "Soft yellow secretion - cerumen" , "Soft yellow substance secreted by glands of a certain organ" , "Otic secretion" .)