Synonyms of the word

stringent

• adj. Strict; binding strongly; making strict requirements; restrictive; rigid; severe.

demanding

• adj. Requiring much endurance, strength, or patience.
• v. present participle of demand.

rigorous

• adj. Showing, causing, or favoring rigour; scrupulously accurate or strict; thorough.
• adj. Severe; intense.

tight

• adj. Firmly held together; compact; not loose or open.
• adj. (of a space, design or arrangement) Narrow, such that it is difficult for something or someone to pass…
• adj. Well-rehearsed and accurate in execution.
• adj. (slang) Intoxicated; drunk or acting like being drunk.
• adj. (slang) Extraordinarily great or special.
• adj. (slang, British (regional)) Mean; unfair; unkind.
• adj. (obsolete) Not ragged; whole; neat; tidy.
• adj. (obsolete) Handy; adroit; brisk.
• adj. (poker) Of a player, who plays very few hands.
• adj. (poker) Using a strategy which involves playing very few hands.
• adv. Firmly, so as not to come loose easily.
• adv. Soundly.
• v. (obsolete) To tighten.