Set of laws protecting a German painkiller (7)
I believe the answer is:
codeine
'painkiller' is the definition.
(codeine is a kind of painkiller)
'set of laws protecting a german' is the wordplay.
'set of laws' becomes 'code'.
'protecting' means one lot of letters goes inside another.
'a german' becomes 'ein' ('a' in German).
'code' placed around 'ein' is 'CODEINE'.
(Other definitions for codeine that I've seen before include "Analgesic drug" , "Pain-relieving derivative of opium" , "An anodyne" , "Morphine-derived analgesic; die once (anag.)" , "Derivative of opium used as an analgesic" .)