Catch reprimand on hospital department (6)
I believe the answer is:
entrap
'catch' is the definition.
(to entrap is to catch with a trap)
'reprimand on hospital department' is the wordplay.
'reprimand' becomes 'rap' (rap is a kind of reprimand).
'on' means one lot of letters go next to another.
'hospital department' becomes 'ENT' (abbreviation for Ear, Nose and Throat department).
'rap' put after 'ent' is 'ENTRAP'.
(Other definitions for entrap that I've seen before include "Take" , "net" , "Parent (anag)" , "Frame -- stitch up" , "Trick or beguile for parent" .)