Dwindle; earmark (4)
I believe the answer is:
flag
I believe this is a double definition.
'dwindle' is the first definition.
(I've seen this in another clue)
'earmark' is the second definition.
(I've seen this in another clue)
(Other definitions for flag that I've seen before include "Plant; paving slab" , "National standard" , "National emblem; tire" , "slow down" , "Standard; tire" .)