Spartan, ascetic (7)
I believe the answer is:
austere
I believe this is a double definition.
'spartan' is the first definition.
(synonyms)
'ascetic' is the second definition.
(I know that ascetic can be written as austere)
(Other definitions for austere that I've seen before include "Severely simple and plain in appearance" , "Plain, cold" , "Serious" , "Bleak" , "Abstemious, strict" .)