Bullish stimulant (7)
I believe the answer is:
taurine
This could be a double definition.
'bullish' is the first definition.
(I've seen this in another clue)
'stimulant' is the second definition.
Both the definition and answer are singular nouns.
Maybe they are linked in a way I don't understand?
Can you help me to learn more?
(Other definitions for taurine that I've seen before include "organic compound" , "Nature I associate with bull-like quality" , "Ruinate, being like bull" , "To do with bulls, bull-like" , "Bully" .)