Go off to get some beer or don’t bother (5,2)
I believe the answer is:
leave be
'don't bother' is the definition.
'go off to get' is the wordplay.
'go off' becomes 'leave' (leaving is a kind of going. I am not sure about the 'off' bit.).
'to get' becomes 'be' ('get' can mean 'come to be').
'leave'+'be'='LEAVE BE'
'some beer or' acts as a link.
This may not be correct. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for leave be that I've seen before include "Refrain from disturbing (someone)" , "Let remain undisturbed" .)