Quietly drink, spilling gallons? This might be baffling! (6)
I believe the answer is:
puzzle
'quietly drink spilling gallons? this might be baffling' is the definition.
Although both the answer and definition are singular nouns, I don't see how one could define the other.
This is the entire clue.
Can you help me to learn more?
(Other definitions for puzzle that I've seen before include "See 13" , "Crossword maybe" , "A game to test ingenuity" , "See 10" , "Conundrum" .)