Difficulty. –N. hardness, impracticability, tough work, hard work, uphill work, hard task, Herculean task, task of Sisyphus, tough job, teaser, rasper, dead lift, dilemma, embarrassment, perplexity, involvement, intricacy, entanglement, crossfire, awkwardness, delicacy, ticklish card to play, deadlock, knot, Gordian knot, net, meshes, maze, coil, crooked path, nice point, delicate point, subtle point, knotty point, vexed question, puzzle, paradox, hard nut to crack, bone to pick, where the shoe pinches, nonplus, quandary, strait, pass, pinch, stress, brunt, critical situation, crisis, trial, rub, emergency, exigency, scramble, scrape, hobble, slough, quagmire, hot water, hornet’s nest, sea of troubles, pretty kettle of fish, pickle, stew, imbroglio, mess, muddle, botch, fuss, bustle, ado, false position, set fast, stand, deadlock, fix, horns of a dilemma, stumbling block.
Facility. –N. ease, easiness, capability, feasibility, flexibility, pliancy, smoothness, convenience, plain sailing, smooth sailing, straight sailing, mere child’s play, holiday task, smooth water, fair wind, smooth road, royal road, clear stage, clear coast, tabula rasa, full play (freedom), disencumbrance, disentanglement, deoppilation, permission.
Thesaurus of Words and Phrases by Peter Mark Roget, M.D., F.R.S. Enlarged by John Lewis Roget, M.A., New Edition Revised and Enlarged by Samuel Romily Roget, M.A. Published by Grosset & Dunlap, the edition is copyright 1941, 1947.