Of the olfactory organ (5)
I believe the answer is:
nasal
'of the olfactory organ' is the definition.
(I know this)
This is all the clue.
(Other definitions for nasal that I've seen before include "Like a twang" , "Of sound, as if it came through the nose" , "Like some spray" , "nozzle" , "old face-saver" .)