Colourless-sounding container (4)
I believe the answer is:
pail
'container' is the definition.
(I know that pail is a type of container)
'colourless-sounding' is the wordplay.
'colourless' becomes 'pale' (similar in meaning).
'sounding' indicates a 'sounds like' (homophone) clue.
'pale' is a homophone of 'PAIL'.
(Other definitions for pail that I've seen before include "Container; sounds like dim" , "water-carrier" , "Kind of bucket - ask Jack and Jill" , "A bucket - the kind Jack and Jill used" , "Milkmaid's bucket?" .)