Break hip: travel for replacement (8)
I believe the answer is:
interval
'break' is the definition.
(I've seen this before)
'hip travel for replacement' is the wordplay.
'hip' becomes 'in' (both can mean fashionable).
'for replacement' indicates an anagram (I've seen this in other clues).
'travel' is an anagram of 'terval'.
'in'+'terval'='INTERVAL'
(Other definitions for interval that I've seen before include "Pause; pitch difference" , "Time break as in play production" , "Break in activity" , "Time between two events" , "Gap during performance" .)