Wild ox is protected by good Parisian (5)
I believe the answer is:
bison
'wild ox' is the definition.
(I've seen this before)
'is protected by good parisian' is the wordplay.
'protected by' means one lot of letters goes inside another (inserted letters are held or protected).
'good parisian' becomes 'bon' ('good' in French).
'is' placed within 'bon' is 'BISON'.
(Other definitions for bison that I've seen before include "US wild ox" , "Buffalo (US)" , "O bins could be full of buffalo" , "Large shaggy wild ox" , "Buffalo Bill's prey" .)