Styptic thread in a hospital department (10)
I believe the answer is:
astringent
'styptic' is the definition.
(I've seen this before)
'thread in a hospital department' is the wordplay.
'thread' becomes 'string' ('string' can be a synonym of 'thread'**).
'in' is an insertion indicator.
'hospital department' becomes 'ent'.
'a'+'ent'='aent'
'string' placed within 'aent' is 'ASTRINGENT'.
(Other definitions for astringent that I've seen before include "medical preparation" , "Styptic" , "for checking bleeding" , "piercing" , "biting" .)