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 understand how this works, but
'unhappy' could be 'low' and 'low' is located in the answer.
The remaining letters 'ger' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
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" .)