Keen to go round ring bypass (5)
I believe the answer is:
avoid
'bypass' is the definition.
(I know that bypass is a more specific form of avoid)
'keen to go round ring' is the wordplay.
'keen' becomes 'avid' (both can mean enthusiastic).
'to go round' means one lot of letters goes inside another.
'ring' becomes 'O' (O is the shape of a ring).
'avid' placed around 'o' is 'AVOID'.
(Other definitions for avoid that I've seen before include "Stay away from or circumvent" , "Steer clear of, dodge" , "Shun, dodge" , "Bypass" , "Eschew" .)