Synonyms of the word

effortful

• adj. Requiring or showing effort.

arduous

• adj. Needing or using up much energy; testing powers of endurance.
• adj. (obsolete) burning; ardent.
• adj. Difficult or exhausting to traverse.

backbreaking

• adj. (figuratively) Of work, very physically tiring.

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.

dragging

• v. present participle of drag.
• n. An instance of something being dragged.

exhausting

• adj. Very tiring.
• v. present participle of exhaust.

grueling

• adj. Alternative spelling of gruelling.

gruelling

• adj. So difficult or taxing as to make one exhausted; backbreaking.

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.

heavy

• adj. (of a physical object) Having great weight.
• adj. (of a topic) Serious, somber.
• adj. Not easy to bear; burdensome; oppressive.
• adj. (Britain, slang, dated) Good.
• adj. (dated, late 1960s, 1970s, US) Profound.
• adj. (of a rate of flow) High, great.
• adj. (slang) Armed.
• adj. (music) Louder, more distorted.
• adj. (of weather) Hot and humid.
• adj. (of a person) Doing the specified activity more intensely than most other people.
• adj. (of food) High in fat or protein; difficult to digest.
• adj. Of great force, power, or intensity; deep or intense.
• adj. Laden to a great extent.
• adj. Laden with that which is weighty; encumbered; burdened; bowed down, either with an actual burden, or with…
• adj. Slow; sluggish; inactive; or lifeless, dull, inanimate, stupid.
• adj. Impeding motion; cloggy; clayey.
• adj. Not raised or leavened.
• adj. Having much body or strength; said of wines or spirits.
• adj. (obsolete) With child; pregnant.
• adv. heavily.
• adv. (India, colloquial) very.
• n. A villain or bad guy; the one responsible for evil or aggressive acts.
• n. (slang) A doorman, bouncer or bodyguard.
• n. (aviation) A large multi-engined aircraft.
• v. (often with "up") To make heavier.
• v. To sadden.
• v. (Australia, New Zealand, informal) To use power and/or wealth to exert influence on, e.g., governments…
• adj. Having the heaves.

labor-intensive

• adj. (American) Requiring a great deal of work, especially physical and manual effort versus capital.

labored

• v. simple past tense and past participle of labor.
• adj. Of an action that is difficult to perform.

laborious

• adj. Requiring much physical effort; toilsome.
• adj. Mentally difficult; painstaking.
• adj. Industrious.

labour-intensive

• adj. (British spelling) alternative form of labor-intensive.

laboured

• v. simple past tense and past participle of labour.
• adj. Of an action that is difficult to perform.
• adj. Of writing or speech or similar, stilted or not natural due to too much effort being used in the production.

leaden

• adj. (dated) Made of lead.
• adj. Pertaining to or resembling lead; heavy, grey, sluggish.
• adj. Dull; darkened with overcast.
• v. (transitive, intransitive) To make or become dull or overcast.

operose

• adj. Wrought with, requiring, or evidencing a lot of labor; hence, tedious; wearisome.
• adj. (of a person) Busy, industrious, or painstaking.

plodding

• v. present participle of plod.
• adj. Progressing slowly and laboriously.
• n. Slow, laborious progress.

punishing

• v. present participle of punish.
• adj. That inflicts punishment.
• adj. Arduous, gruelling.
• n. Punishment.

straining

• v. present participle of strain.
• n. The act by which one strains.

strenuous

• adj. vigorous, energetic, ardent, zealous.
• adj. Requiring great exertion.

tiring

• v. present participle of tire.
• n. (uncountable) Action of the verb to tire.
• n. (falconry) Bits of bone and tough organic material from a corpse given to hawks to abate their hunger.
• adj. That tires or tire.

toilsome

• adj. Requiring continuous physical effort; laborious.

wearing

• adj. intended to be worn.
• adj. causing tiredness.
• adj. causing erosion.
• n. The mechanical process of eroding or grinding.
• n. The act by which something is worn.
• n. That which is worn; clothes; garments.
• v. present participle of wear.

wearying

• v. present participle of weary.