Austere section put in hospital (7)
I believe the answer is:
spartan
'austere' is the definition.
('spartan' can be a synonym of 'austere')
'section put in hospital' is the wordplay.
'section' becomes 'part' ('part' can be a synonym of 'section'**).
'put in' is an insertion indicator.
'hospital' becomes 'san' (I've seen this in other clues).
'part' put within 'san' is 'SPARTAN'.
(Other definitions for spartan that I've seen before include "Basic" , "Of conditions, simple and harsh as for ancient Greeks" , "Plain" , "Austere, lacking comfort" , "Disciplined person" .)