That teacher's demands are stringent — she wants the homework typed in her favorite font, on special paper, and each essay must be exactly 45 lines!
While the word stringent might seem foreign, if you're afflicted with pimples, you'll know the word astringent. An astringent causes your skin to tighten like it's shrinking your pores. This tightening, constricting feel describes stringent with regard to rules. Stringent safety procedures prevent accidents in a dangerous work environment. And restaurants must adhere to stringent health regulations.