Vessel taking a showman's dog to jail (4,3)
I believe the answer is:
toby jug
'vessel' is the definition.
(I've seen this before)
'a showman's dog to jail' is the wordplay.
I cannot really understand how this works, but
'dog' could be 'toby' (I've seen this before) and 'toby' is found in the answer.
'jail' could be 'jug' (synonyms) and 'jug' is present in the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
'taking' is the link.
Can you help me to learn more?
(Other definitions for toby jug that I've seen before include "Vessel shaped like a stout man" , "Figurine mug" , "one possibly charged with drink" , "drinking-vessel?" , "Beer mug in the shape of a man in a tricorn hat" .)