Notice mole (3)
I believe the answer is:
spy
This clue is a double definition.
'notice' is the first definition.
(thesaurus)
'mole' is the second definition.
(I've seen this before)
(Other definitions for spy that I've seen before include "Person who secretly collects information as for government" , "One gathers information on enemies" , "Spot" , "Watch covertly like secret agent" , "Glimpse" .)