Look unhappy when given a shiner! (6)
I believe the answer is:
glower
'look' is the definition.
(I know that glower is a type of stare)
'unhappy when given a shiner' is the wordplay.
I cannot quite see how this works, but
'unhappy' could be 'low' and 'low' is found in the answer.
The remaining letters 'ger' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for glower that I've seen before include "Angry and sullen look" , "burning ember, say?" , "firefly?" , "Fierce look" , "Not a good look" .)