austere in WordNet English dictionary

1. practicing great self-denial
   "Be systematically ascetic...do...something for no other reason than that you would rather not do it"- William James; "a desert nomad's austere life"; "a spartan diet"; "a spartan existence"
   ascetic  ascetical  austere  spartan 
   
2. of a stern or strict bearing or demeanor; forbidding in aspect
   "an austere expression"; "a stern face"
   austere  stern 
   
3. severely simple
   "a stark interior"
   austere  severe  stark  stern