New attempt to return drink to mug (6)
I believe the answer is:
noggin
'mug' is the definition.
(noggin is a type of mug or container)
'new attempt to return drink' is the wordplay.
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'attempt' becomes 'go' (go is a kind of attempt).
'to return' says the letters should be written backwards.
'drink' becomes 'gin' (gin is a kind of drink).
'go' in reverse letter order is 'og'.
'n'+'og'+'gin'='NOGGIN'
'to' acts as a link.
(Other definitions for noggin that I've seen before include "Small measure of alcohol, about 1/4 pint" , "Small measure of spirits or slangy head" , "Small quantity of spirits" , "Small amount of liquor" , "Measure of alcohol, about a quarter pint" .)