Wave forward from large vessel (6)
I believe the answer is:
flagon
'large vessel' is the definition.
'flagon' can be an answer for 'vessel' (flagon is a kind of vessel). I am not sure about the 'large' bit.
'wave forward' is the wordplay.
'wave' becomes 'flag' (I can't justify this - if you can you should believe this answer much more).
'forward' becomes 'on'.
'flag'+'on'='FLAGON'
'from' acts as a link.
Can you help me to learn more?
(Other definitions for flagon that I've seen before include "Large wine vessel" , "Large drinks container" , "Large rounded bottle, may contain cider" , "Large vessel for beverages" , "Large rounded bottle for cider or wine" .)