Crossword Genius

Marijuana for the informer (5)

Ross

I believe the answer is:

I believe this is a double definition.

'marijuana' is the first definition.
(synonyms)

'the informer' is the second definition.
(I've seen this before)

'for' is the link.

(Other definitions for grass that I've seen before include "Drug", "Soporific", "Plant used for lawns", "Weed", "sing?".)