Is too bright and one lowers (6)
I believe the answer is:
glares
'lowers' is the definition.
The definition and answer can be both related to bodily activities as well as being verbs in their -s form.
Maybe they are linked in a way I don't understand?
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for glares that I've seen before include "Angry stares" , "Looks hotly and angrily" , "Stares angrily" .)