Cloak-and-dagger figure (3)
I believe the answer is:
spy
'cloak-and-dagger figure' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for spy that I've seen before include "Spot" , "Catch sight of" , "Undercover agent" , "Mole, agent" , "Notice" .)