Avoid being involved in support (5,2)
I believe the answer is:
stand by
'support' is the definition.
(I've seen this before)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for stand by that I've seen before include "One ready for emergency duty" , "Act like supporters" , "One ready to step in" , "Remain loyal to" , "last-minute ticket" .)