Cross removed from outside, never to be broken? (7)
I believe the answer is:
eternal
'never to be broken?' is the definition.
'cross removed from outside' is the wordplay.
'cross' becomes 'x'.
'removed from' is a deletion indicator.
'outside' becomes 'external' ('external' can be a synonym of 'outside').
'external' with 'x' taken away is 'ETERNAL'.
(Other definitions for eternal that I've seen before include "Not stopping" , "going on for ever" , "Infinite - endless" , "abiding" , "Such a city is Rome" .)