Adjective hard, difficult
Synonyms: arduous, backbreaking, burdensome, effortful, fatiguing, forced, heavy, herculean, labored, onerous, operose, ponderous, rough go, stiff, strained, strenuous, tiresome, toilsome, tough, tough job, wearing, wearisome, wicked
Antonyms: easy, effortless, facile, simple, trivial
Adjective hardworking
Synonyms: active, assiduous, diligent, indefatigable, industrious, operose, painstaking, persevering, sedulous, tireless, unflagging
Antonyms: idle, lackadaisical, lazy, reticent