What does the term "austere" best mean?

The term "austere" best describes a quality of being strict or severe in appearance, manner, or attitude. It often implies a lack of ornamentation or simplicity, which can translate into a strict or stringent environment or behavior. In various contexts, "austere" can refer to a lifestyle that avoids excess and frivolity, focusing instead on discipline and simplicity, often with a sense of somberness. This aligns closely with the idea of being strict, where rules or standards are adhered to without leniency.

In contrast, the other choices present meanings that do not capture the essence of "austere." For instance, "incredible" suggests something extraordinary or hard to believe, "luster" refers to shine or brilliance, and "sanitary" relates to cleanliness and hygiene. None of these definitions resonate with the concept of strictness or severity inherent in the term "austere."