A labyrinth intended, we hear, to cause consternation (9)
I believe the answer is:
amazement
'consternation' is the definition.
'a labyrinth intended we hear' is the wordplay.
'labyrinth' becomes 'maze' ('maze' can be a synonym of 'labyrinth').
'intended' becomes 'meant' (meaning is a kind of intending).
'we hear' indicates a 'sounds like' (homophone) clue.
'meant' is a homophone of 'ment'.
'a'+'maze'+'ment'='AMAZEMENT'
'to cause' is the link.
(Other definitions for amazement that I've seen before include "Great surprise" , "Stupefaction" , "Great astonishment" , "Shock" , "Astonishment, wonderment" .)