Large amount of drink - reduced concern - one’s driven wildly (6,3)

I believe the answer is:

bumper car

'one's driven wildly' is the definition.
(car driven at a fairground)

'large amount of drink reduced concern' is the wordplay.
'large amount of drink' becomes 'bumper' (historical drinking vessel).
'reduced' means to remove the last letter.
'concern' becomes 'care' (synonyms).
'care' with its last letter taken off is 'car'.
'bumper'+'car'='BUMPER CAR'

(Another definition for bumper car that I've seen is " one's driven to a series of bashes".)

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