Outstanding hospital department with parts separated by tunnel (7)
I believe the answer is:
eminent
'outstanding' is the definition.
(eminent can mean esteemed or outstanding)
'hospital department with parts separated by tunnel' is the wordplay.
'hospital department' becomes 'ENT' (abbreviation for Ear, Nose and Throat department).
'with parts separated by' indicates putting letters inside (inserted letters split the word into two parts).
'tunnel' becomes 'mine' (I've seen this in other clues).
'ent' going around 'mine' is 'EMINENT'.
(Other definitions for eminent that I've seen before include "High" , "Famous and admired" , "Distinguished, prominent" , "Respected; notable" , "Important" .)