Synonyms of the word

demanding

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

difficult

• adj. Hard, not easy, requiring much effort.
• adj. (often of a person, or a horse, etc) Hard to manage, uncooperative, troublesome.
• adj. (obsolete) Unable or unwilling.
• v. (obsolete, transitive) To make difficult; to impede; to perplex.

exacting

• adj. Making excessive demands; difficult to satisfy.
• adj. (of an action, task, etc) Requiring precise accuracy, great care, effort, or attention.
• adj. (of a person or organization) Characterized by exaction.
• v. present participle of exact.

exigent

• adj. Urgent; needing immediate action.
• adj. Demanding; needing great effort.
• n. (archaic) Extremity; end; limit; pressing urgency.
• n. (obsolete, Britain, law) The name of a writ in proceedings before outlawry.

hard

• adj. (of material or fluid) Having a severe property; presenting difficulty.
• adj. (personal or social) Having a severe property; presenting difficulty.
• adj. Unquestionable.
• adj. (of a road intersection) Having a comparatively larger or a ninety-degree angle.
• adj. (slang, vulgar, of a male) Sexually aroused.
• adj. (bodybuilding) Having muscles that are tightened as a result of intense, regular exercise.
• adj. (phonetics, not comparable).
• adj. (art) Having a severe property; presenting a barrier to enjoyment.
• adj. (not comparable) In the form of a hard copy.
• adv. (manner) With much force or effort.
• adv. (manner) With difficulty.
• adv. (obsolete) So as to raise difficulties.
• adv. (manner) Compactly.
• adv. (now archaic) Near, close.
• n. (countable, nautical) A firm or paved beach or slope convenient for hauling vessels out of the water.
• n. (uncountable, drugs, colloquial, slang) crack cocaine.

needy

• adj. In need, poor.
• adj. Desiring constant affirmation, lacking in self confidence.

rigorous

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

stern

• adj. Having a hardness and severity of nature or manner.
• adj. Grim and forbidding in appearance.
• n. (nautical) The rear part or after end of a ship or vessel.
• n. (figuratively) The post of management or direction.
• n. The hinder part of anything.
• n. The tail of an animal; now used only of the tail of a dog.
• n. A bird, the black tern.

strict

• adj. Strained; drawn close; tight.
• adj. Tense; not relaxed.
• adj. Exact; accurate; precise; rigorously nice.
• adj. Governed or governing by exact rules; observing exact rules; severe; rigorous.
• adj. Rigidly interpreted; exactly limited; confined; restricted.
• adj. (botany) Upright, or straight and narrow; — said of the shape of the plants or their flower clusters.
• adj. Severe in discipline.

stringent

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

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.

tightened

• v. simple past tense and past participle of tighten.