Abstemious individual (7)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
ascetic
(Other definitions for ascetic that I've seen before include "One practises self-denial as a spiritual discipline" , "Self-denying, often for religious reasons" , "Person who leads a severely simple life" , "Self-disciplined person" , "reclusive" .)