plain, strict, or serious
austere - plain
The meaning of the word ‘austere’ as seen above can be adapted for various uses. It can be used to refer to a person who exhibits those traits, a strict way of life, something basic and lacking in comfort, or to express a severe limit on money or goods. The term is not necessarily always a negative; for example an austere diet may be good for you, but it never connotes something pleasurable.
The accommodation was clean, but quite austere. I would have preferred to stay somewhere more comfortable.
My grandfather was an austere man who rarely laughed and never joked.
After the financial crash, society was reduced to a state of austerity for a number of years.