Awe-inspiring (12)
I believe the answer is:
breathtaking
'awe-inspiring' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for breathtaking that I've seen before include "Awe-inspiring" , "Causing astonishment" , "Moving" , "way of getting air into the lungs" , "if one is not one is dead?" .)