Livener kept in bucket, on ice (5)
I believe the answer is:
tonic
'livener' is the definition.
(a tonic livens you up)
'kept in bucket on ice' is the wordplay.
'kept in' says the answer is hidden in the clue.
'TONIC' is hidden in the letters of 'bucket on ice'.
(Other definitions for tonic that I've seen before include "something providing a boost" , "Small drink of spirits" , "Carbonated mixer" , "Medical restorative" , "shot in the arm" .)