We're off to get jug (4)
I believe the answer is:
ewer
'jug' is the definition.
(type of vessel)
'we're off' is the wordplay.
'off' is an anagram indicator.
'were' is an anagram of 'EWER'.
'to get' acts as a link.
(Other definitions for ewer that I've seen before include "A wide-lipped jug" , "Jar for water" , "Water-jar" , "Decorative pitcher" , "Big jug" .)