Waylay a doctor attached to American hospital (6)
I believe the answer is:
ambush
'waylay' is the definition.
('ambush' can be a synonym of 'waylay')
'a doctor attached to american hospital' is the wordplay.
'doctor' becomes 'mb' (Bachelor of Medicine, Medicinae Baccalaureus**).
'attached to' says to put letters next to each other.
'american' becomes 'us'.
'hospital' becomes 'h'.
'a'+'mb'+'us'+'h'='AMBUSH'
(Other definitions for ambush that I've seen before include "Waylaying" , "Jump" , "Lie in wait and attack" , "Await and intercept unexpectedly" , "Waylay" .)