Make off before the judge stands (2,6)
I believe the answer is:
up sticks
'make off' is the definition.
(both can mean to leave a place)
'before the judge stands' is the wordplay.
'before the judge' becomes 'up' (as in being up in court).
'stands' becomes 'sticks' (both can mean to persevere or endure).
'up'+'sticks'='UP STICKS'
(Other definitions for up sticks that I've seen before include "Move house(colloq.)" , "Move away without warning" , "Make off" .)