A shopper, perhaps, giving things away (8)
I believe the answer is:
telltale
'a shopper' is the definition.
The definition and answer can be both people as well as being singular nouns.
Perhaps you can see a link between them that I don't see?
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for telltale that I've seen before include "One revealing secrets" , "Blabbermouth, snitch" , "Monitoring device - gossip" , "Blabber-mouth, can't keep a secret" , "Blabbing person" .)