Surfboard application (3)
I believe the answer is:
wax
'surfboard application' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for wax that I've seen before include "increase like stuff in ears" , "Cere - grow larger" , "Candle material" , "Yellow stuff secreted in ear" , "Increase (as moon's phase)" .)