Drug a German injected into Morse? (7)
I believe the answer is:
codeine
'drug' is the definition.
(codeine is a kind of drug)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for codeine that I've seen before include "Niece, do take this drug" , "Common opium-based tablet used to relieve pain" , "Mild narcotic used as a pain-killer" , "Derivative of opium used as an analgesic" , "Painkiller derived from opium" .)