Austere, harsh (6)
I believe the answer is:
severe
This clue is a double definition.
'austere' is the first definition.
(synonyms)
'harsh' is the second definition.
(I've seen this before)
(Other definitions for severe that I've seen before include "Serious or strict" , "Strict, hard" , "Drastic" , "Very bad" , "Harsh and punitive" .)