What a chest expander will never do? (6)
I believe the answer is:
exhale
'do?' is the definition.
The definition and answer can be both related to bodily activities as well as being verbs in their base form.
Perhaps there's an association between them I don't understand?
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for exhale that I've seen before include "Expel air from the lungs" , "Give out" , "send forth wind" , "Emit breath" , "expire" .)