Spot a traitor (4)
I believe the answer is:
mole
This clue could be a double definition.
'spot' is the first definition.
(spot or blemish on the skin)
'a traitor' is the second definition.
The answer and definition can be both people as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
Can you help me to learn more?
(Other definitions for mole that I've seen before include "Skin spot; breakwater" , "Small spot - small mammal" , "beauty spot" , "Spot - traitor" , "Dark spot on skin or burrowing animal" .)