Shun key hospital we set up (6)
I believe the answer is:
eschew
'shun' is the definition.
('eschew' can be a synonym of 'shun')
'key hospital we set up' is the wordplay.
'key' becomes 'esc' ('Escape' key on a computer keyboard).
'hospital' becomes 'h'.
'set up' is a reversal indicator.
'we' backwards is 'ew'.
'esc'+'h'+'ew'='ESCHEW'
(Other definitions for eschew that I've seen before include "'Stay clear of, shun (6)'" , "Abstain from, shun" , "Steer clear of" , "'Avoid, keep away from (6)'" , "Avoid or abstain from, action or food" .)