Austere
Part of speech: adjective
Definition: Grim or severe in manner or appearance Lacking trivial decoration; not extravagant or gaudy
Example sentence: My face lends itself to austere characters, and unless they're two-dimensional, I will do them. Any actor will tell you that an interesting villain is much more interesting to play.
Ascetic
Part of speech: adjective
Definition: Of or relating to ascetics; characterized by rigorous self-denial or self-discipline; austere; abstinent; involving a withholding of physical pleasure.
Part of speech: noun
Definition: One who is devoted to the practice of self-denial, either through seclusion or stringent abstinence.
Example sentence: No sane man can afford to dispense with debilitating pleasures; no ascetic can be considered reliably sane.