List of tough synonyms and tough related words.
Antaeus, Atlas, Briareus, Brobdingnagian, Charles Atlas, Cyclops, Goliath, Herculean, Hercules, Mafioso, OK, Polyphemus, Samson, Spartan, Spartanic, Superman, Tarzan, Titan, Young Turk, abiding, abstruse, ace-high, acute, adamant, adamantine, adherent, adhesive, age-long, aged, amylaceous, ancient, antique, arbitrary, arduous, astringent, athletic, austere, authoritarian, backbreaking, bad, baffling, bang-up, battler, beast, beldam, belligerent, belted knight, berserk, berserker, beyond one, bickerer, blade, bomber, bony, bonzer, boss, bravo, brawler, brawny, bruiser, brutal, brute, bulky, bulldogged, bulldoggish, bulldoggy, bullheaded, bully, bullyboy, burdensome, burly, but good, callous, cartilaginous, cement, cemental, chewy, chronic, clabbered, clammy, clingy, clotted, coagulated, cohesive, cold, colossus, combatant, competitor, complex, complicated, concrete, confirmed, constant, contender, contestant, continuing, cool, coriaceous, corking, corneous, crabbed, crackerjack, cramp, critical, crushing, curdled, cutting, dandy, delicate, delicious, demanding, demon, dense, devil, diamondlike, difficile, difficult, disputant, diuturnal, doughty, doughy, dour, dragon, drastic, ducky, duelist, durable, dure, effortful, enduring, enforcer, evergreen, exacting, excessive, exigent, exorbitant, extravagant, extreme, fab, fencer, feuder, fibrous, fiend, fierce, fighter, fighting cock, fine and dandy, fire-eater, firebrand, firm, fixed, flintlike, flinty, foilsman, forced, formidable, furious, fury, game, gamecock, gamy, garbled, gaumy, gear, gelatinous, giant, gladiator, glairy, gluelike, gluey, glutenous, glutinose, glutinous, gooey, goon, gorilla, granitelike, granitic, great, grim, gristly, gritty, groovy, grueling, grumous, gumbo, gumbolike, gumlike, gummous, gummy, gun, gunsel, gutsy, gutty, hairy, hard, hard as nails, hard to understand, hard-bitten, hard-boiled, hard-earned, hard-fought, hard-line, hard-nosed, hard-set, hardened, hardhearted, hardnose, hardy, harsh, hatchet man, heavy, hefty, hell-raiser, hellcat, hellhound, hellion, holy terror, hood, hoodlum, hooligan, horny, hot, hothead, hotspur, hunky-dory, icy, immoderate, immutable, incendiary, inflexible, inspissated, intemperate, intense, intractable, intransient, intrepid, intricate, inured, inveterate, irksome, iron-hard, ironlike, jam-up, jawbreaking, jelled, jellied, jellylike, jouster, jumbled, just dandy, keen, killer, killing, knight, knotted, knotty, labored, laborious, lapideous, lasting, leatherlike, leathery, lithoid, lithoidal, long-lasting, long-lived, long-standing, long-term, longeval, longevous, macrobiotic, mad dog, madcap, manly, marble, marblelike, marvy, massive, mean, meticulous, mettlesome, militant, monster, mucilaginous, mucker, mug, mugger, muscle man, muscular, mystifying, narrow, neat, nervy, nifty, no picnic, nobby, not easy, obdurate, obfuscated, obscure, obscured, obstinate, of long duration, of long standing, okay, onerous, operose, oppressive, osseous, out of sight, outrageous, overtechnical, painful, pasty, peachy, peachy-keen, perdurable, perduring, perennial, permanent, perpetual, perplexed, perplexing, persistent, persisting, pertinacious, piercing, plucky, plug-ugly, powerful, powerhouse, procrustean, punishing, punk, puzzling, quarreler, rapist, red-blooded, refractory, remaining, resistant, resistive, resolute, revolutionary, rigid, rigorous, rioter, ripping, rival, rocklike, rocky, rodman, ropy, rough, roughneck, rowdy, ruffian, rugged, rum, sabreur, savage, scrambled, scrapper, scrumptious, scuffler, self-adhesive, sempervirent, set with thorns, severe, sharp, she-wolf, sinewy, slabby, slap-up, slimy, slithery, smashing, solid, something else, sound, spiffing, spiffy, spiny, spirited, spiritful, spitfire, splitting, spunky, squabbler, stable, stalwart, starchy, staying, steadfast, steady, steellike, steely, steep, stern, stickable, sticky, stiff, stodgy, stonelike, stony, stout, strained, strapping, strenuous, strict, stringent, stringy, strong, strong arm, strong man, strong-arm man, strong-armer, struggler, stubborn, stunning, sturdy, substantial, swashbuckler, swell, sword, swordplayer, swordsman, syrupy, tacky, taut, taxing, tenacious, termagant, terror, terrorist, the mighty, the strong, thick, thickened, thorny, thug, ticklish, tiger, tigress, tilter, toilsome, torpedo, tough as leather, tough guy, tower of strength, tremelloid, tremellose, tricky, trigger man, troublesome, tussler, ugly customer, unalterable, unbending, unbreakable, uncaring, uncompromising, unconscionable, underprivileged, unfading, unfeeling, ungiving, unsentimental, unsparing, unsympathetic, untiring, unyielding, uphill, vehement, venomous, vigorous, violent, virago, virile, virulent, viscid, viscose, viscous, vital, vixen, wearisome, well-built, well-constructed, well-founded, well-grounded, well-made, wicked, wild beast, wiry, witch, withstanding, wizard, wolf, wrangler, yahoo