Synonyms for Tough:

adj.

all (adjective)
rugged, hard.
courageous (adjective)
fearless.
difficult (adjective)
thorny, formidable, difficult, wearying, cantankerous, trying, uphill, bothersome, oppressive, tricky, strenuous, complex, ticklish, tight, finicky, wearisome, demanding, stressful, cumbersome, laborious, rough, severe, troublesome, rugged, burdensome, wearing, complicated, grinding, onerous, toilsome, adverse, knotty, fussy, hard, harsh, contrary, arduous.
difficult, laborious (adjective)
effortful, weighty, Resisting, troublesome, exigent, intricate, oppressive, trying, arduous, thorny, puzzling, onerous, burdensome, knotty, uphill, taxing, demanding, strenuous, toilsome.
durable (adjective)
persistent.
effortful (adjective)
effortful.
excellent (adjective)
fine, excellent, first class, premium.
healthy (adjective)
healthy.
insensitive (adjective)
cold-blooded, blunt, unconcerned, hard-boiled, passionless, hardhearted, nonchalant, objective, indifferent, apathetic, unfeeling, passive, unemotional, insensitive, aloof, numb, ruthless, emotionless, heartless, dispassionate, unsympathetic, callous, uncompassionate, hardened, anesthetized, cool, detached, hard, stony.
leathery (adjective)
leatherlike, coriaceous.
obstinate, rough (adjective)
fierce, callous, exacting, uncontrollable, stern, uncompromising, harsh, savage, terrible, pugnacious, severe, strict, violent, vicious, desperate, ruffianly, unbending, headstrong, obdurate, unforgiving, resolute, stubborn, ruthless, hard-boiled, ferocious.
rocklike (adjective)
hard.
rough (adjective)
rough-and-tumble.
severe (adjective)
severe.
stable (adjective)
solid as a rock.
strong (adjective)
wiry, mighty, husky, brawny, sinewy, muscular, mettlesome, iron-willed, sturdy, powerful, stable, strong, robust, vital, virile, formidable, stout, potent, heavy-duty, firm, vigorous, energetic.
sturdy, strong (adjective)
rigid, robust, brawny, indigestible, mighty, unbreakable, durable, rugged, sinewy, leathery, tight, dense, firm, hard-bitten, solid, stout, stiff, unyielding, healthy, vigorous, tenacious, fibrous, hard, hardened.
tenacious (adjective)
undaunted, dauntless, hard, unflagging, strong, fervent, spunky, plucky, bullheaded, flintlike, steadfast, diligent, courageous, persevering, headstrong, determined, faithful, devoted, stiff, brave, obdurate, insistent, hearty, obstinate, decisive, persistent, dogged, stubborn, resolute, strong-willed, stony, true, bold, staunch, tenacious, bulldogged, indefatigable, enduring, tireless, indomitable.

n.

arsonist, drug lord, accessory, abductor, fence, con woman, child molester, con artist, CONMAN, drug baron. athletic, Hunky, Hard-handed, continue, able-bodied. exacting, rigorous, effortful, taxing, hardline, weighty, stringent, unforgiving, exigent. durable, heavy-duty, rough-and-tumble, action, irresistible, knockabout, solid as a rock. flyblown, rigid, bony, boneless, lean, Skinless, jellied, jerk, strict, meaty. too bad, tough shit, my heart bleeds (for someone), you're breaking my heart, tough luck, purpose. sweat out, endure. combatant (noun)
bruiser, battler, struggler, duelist, pugilist, fighter, mercenary, opponent, gladiator, assailant, thug, quarreler, swordsman, man-at-arms, adversary, militant, rioter, contestant, foe, competitor, warrior, brawler, soldier, enemy, antagonist, bully, combatant, Jouster, rival.
evildoer (noun)
cutthroat, vulture, thief, monster, gunman, demon, scoundrel, bad guy, ruffian, hoodlum, terrorist, desperado, fiend, brute, criminal, vandal, snake, vampire, wrongdoer, law breaker, ogre, crook, evildoer, viper, tyrant, hooligan.
gangster (noun)
goon, bruiser.
hardy (noun)
healthy, sound, capable.
person (noun)
street fighter.
person who is rowdy, mean (noun)
bully, rough, brute, ruffian, bruiser, roughneck, rowdy, goon, hooligan, criminal, thug, hood, punk, hoodlum.
tough (noun)
coriaceous, unsentimental, yob, hooligan, punk, hard-boiled, strong-armer, hard-bitten, unchewable, fibrous, chewy, leatherlike, hoodlum, tough-minded, inured, bad, yobbo, street fighter, weather-beaten, difficult, toughened, gristly, calloused, leathered, cartilaginous, hardened, enured, hood, hempen, bully, toughie, yobo, thickened, hard, pugnacious, ruffianly, thug, stringy, ruffian, goon, rowdy, roughneck, sturdy, rugged, violent, rubbery, uncomfortable, sinewy, leathery.
unfavorable (noun)
unfortunate, untimely, unfavorable.

v.

enduring (verb)
durable.
persevere (verb)
persist, endure.

Other synonyms:

fierce, irresistible, boneless, knockabout, unbreakable, Skinless, stringent, rough-and-tumble, healthy, effortful, hardline, meaty, Hunky, jellied, Hard-handed. athletic, exacting, jerk, ambitious, flyblown, heavy-duty, tall. exigent, weighty, strict, rigorous, bony. taxing. rigid. solid. lean. Other relevant words:
hard-bitten, durable, roughneck, rigid.

Usage examples for tough

  1. " Take that man," he said sharply, pointing to the tough whom the colonel held covered, and two men seized him from behind. – Christmas Eve on Lonesome and Other Stories by John Fox, Jr.
  2. No doubt drinkin', smokin', an' gamblin' makes men jolly- them at least that's tough an' that wins! – Charlie to the Rescue by R.M. Ballantyne
  3. Tough luck we couldn't 'a' made a clean sweep of that bunch, huh? – The Heart of the Range by William Patterson White