Characterized by effort to the point of exhaustion; especially physical effort:
— Spent many laborious hours on the project.

synonyms: arduous, backbreaking, grueling, gruelling, hard, heavy, operose, punishing, toilsome.

Roget 686: laboring etc. v.. laborious, operose^†, elaborate; strained; toilsome, troublesome, wearisome; uphill; herculean, gymnastic, palestric^†.    hard-working, painstaking; strenuous, energetic.    hard at work, on the stretch.    ... show more

Roget 704: difficult, not easy, hard, tough; troublesome, toilsome, irksome; operose^†, laborious, onerous, arduous, Herculean, formidable; sooner said than done; more easily said than done, easier said than done.    difficult to deal with, hard to deal with; ill-conditioned, crabbed, crabby; not to be handled with kid gloves, not made with rose water.    awkward, unwieldy, unmanageable; intractable, stubborn etc. (obstinate) 606; perverse, refractory, plaguy^†, trying, thorny, rugged; knotted, knotty; invious^†; pathless, trackless; labyrinthine etc. (convoluted) 248; intricate, complicated etc. (tangled) 59; impracticable etc. (impossible) 471; not feasible etc. 470; desperate etc. (hopeless) 859.    embarrassing, perplexing etc. (uncertain) 475; delicate, ticklish, critical; beset with difficulties, full of difficulties, surrounded by difficulties, entangled by difficulties, encompassed with difficulties.    under a difficulty; in a box; in difficulty, in hot water, in the suds, in a cleft stick, in a fix, in the wrong box, in a scrape etc. n., in deep water, in a fine pickle; in extremis; between two stools, between Scylla and Charybdis; surrounded by shoals, surrounded by breakers, surrounded by quicksands; at cross purposes; not out of the wood.    reduced to straits; hard pressed, sorely pressed; run hard; pinched, put to it, straitened; hard up, hard put to it, hard set; put to one's shifts; puzzled, at a loss, etc. (uncertain) 475; at the end of one's tether, at the end of one's rope, at one's wit's end, at a nonplus, at a standstill; graveled, nonplused, nonplussed, stranded, aground; stuck fast, set fast; up a tree, at bay, aux abois [Fr.], driven into a corner, driven from pillar to post, driven to extremity, driven to one's wit's end, driven to the wall; au bout de son Latin; out of one's depth; thrown out.    accomplished with difficulty; hard-fought, hard-earned.    ... show more

Polish: morderczy, katorżniczy