Busy working but drinking, say (2,3,2)
I believe the answer is:
on the go
'busy' is the definition.
(similar in meaning)
'working but drinking say' is the wordplay.
'working' becomes 'on' (on can mean working or activated).
'but' becomes 'tho' (I've seen this in other clues).
'drinking' is an insertion indicator (inserted letters are consumed or drunk).
'say' becomes 'eg' (both can mean 'for example').
'tho' placed around 'eg' is 'thego'.
'on'+'thego'='ON THE GO'
(Other definitions for on the go that I've seen before include "Busy and active" , "Moving -- active" , "Active, in constant motion" , "Running around busily" , "ready to start monopoly?" .)