A somewhat shocking drink? (3)
I believe the answer is:
jar
'drink?' is the definition.
(colloquial)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for jar that I've seen before include "Glass of beer; clash" , "Wide-mouthed vessel" , "Container; be incongruous" , "Enduring courage" , "(Jam) pot" .)