Never breaking bottle (5)
I believe the answer is:
nerve
'bottle' is the definition.
(both can mean courage)
'never breaking' is the wordplay.
'breaking' is an anagram indicator.
'never' is an anagram of 'NERVE'.
(Other definitions for nerve that I've seen before include "Impulse transmitter - bottle" , "Hold it and maintain courage" , "Fibre to carry instructions between brain and body" , "displaying self-possession" , "Bodily fibre carrying sensation" .)