Waste carrier avoiding small vessel (4)
I believe the answer is:
ewer
'vessel' is the definition.
(ewer is a kind of vessel)
'waste carrier avoiding small' is the wordplay.
'waste carrier' becomes 'sewer' (I've seen this in another clue).
'avoiding' suggests deleting specific letters.
'small' becomes 's' (abbreviation - e.g. clothes size).
'sewer' with 's' removed is 'EWER'.
(Other definitions for ewer that I've seen before include "Decorative pitcher" , "Large water jug" , "Vessel for pouring" , "Large, wide-mouthed jug" , "Big jug" .)