The sound of wine unceremoniously poured? (5)

I believe the answer is:

plonk

I'm a little stuck... Click here to teach me more about this clue!

'the sound' is the definition.
(plonk is a kind of sound)

I don't understand how the remainder of the clue works.

(Other definitions for plonk that I've seen before include "cheap drink" , "Wine - put down with a thud" , "Put down - cheap wine" , "Set down" , "Drop" .)

I've seen this clue in the Evening Standard.

Want a hint initially instead of a full solution? Install my app