[1] : The Collaborative International Dictionary of English v.0.48

tenacious \tena"cious\, a. l. tenax, -acis, from tenere to
   hold. see tenable, and cf. tenace.
   1. holding fast, or inclined to hold fast; inclined to retain
      what is in possession; as, men tenacious of their just
      rights.
      1913 webster

   2. apt to retain; retentive; as, a tenacious memory.
      1913 webster

   3. having parts apt to adhere to each other; cohesive; tough;
      as, steel is a tenacious metal; tar is more tenacious than
      oil. --sir i. newton.
      1913 webster

   4. apt to adhere to another substance; glutinous; viscous;
      sticking; adhesive. "female feet, too weak to struggle
      with tenacious clay." --cowper.
      1913 webster

   5. niggardly; closefisted; miserly. --ainsworth.
      1913 webster

   6. holding stoutly to one's opinion or purpose; obstinate;
      stubborn.
      1913 webster -- tena"ciously, adv. --
      tena"ciousness, n.
      1913 webster
see also:
tenable tenace tena"ciously tena"ciousness 

[2] : WordNet (r) 2.0

tenacious
     adj 1: stubbornly unyielding; "dogged persistence"; "dour
            determination"; "the most vocal and pertinacious of
            all the critics"; "a mind not gifted to discover truth
            but tenacious to hold it"- t.s.eliot; "men tenacious
            of opinion" syn: bulldog, dogged, dour, pertinacious,
             unyielding
     2: of memory having greater than average range; "a long
        memory especially for insults"; "a tenacious memory" syn:
         long
     3: sticking together; "two coherent sheets"; "tenacious burrs"
        syn: coherent
see also:
bulldog dogged dour pertinacious unyielding long 
coherent 

[3] : Moby Thesaurus II by Grady Ward, 1.0

222 moby thesaurus words for "tenacious":
   adamant, adherent, adhesive, amylaceous, assiduous, balking, balky,
   bigoted, bound, bound and determined, bulldogged, bulldoggish,
   bulldoggy, bulletheaded, bullheaded, cartilaginous, case-hardened,
   chewy, clabbered, clammy, clinging, clingy, clotted, coagulated,
   cohesive, committed, constant, continuing, coriaceous, curdled,
   decided, decisive, dedicated, definite, determined, devoted,
   diligent, dogged, dogmatic, doughy, durable, earnest, enduring,
   faithful, fanatic, fibrous, firm, fixed, game, gamy, gaumy,
   gelatinous, glairy, gluelike, gluey, glutenous, glutinose,
   glutinous, good, gooey, grasping, gripping, gristly, gritty,
   grumous, gumbo, gumbolike, gumlike, gummous, gummy, gutsy, gutty,
   hard, hardheaded, hardy, headstrong, heavy, holding, immovable,
   immutable, inalterable, indefatigable, indomitable, industrious,
   inflexible, insistent, inspissated, intolerant, intransigent,
   invincible, jelled, jellied, jellylike, keeping, lasting,
   leatherlike, leathery, loyal, maintaining, mettlesome,
   mucilaginous, mulish, nervy, never-tiring, obdurate, obstinate,
   opinionated, overzealous, pasty, patient, patient as job,
   permanent, perseverant, persevering, persistent, persisting,
   pertinacious, pigheaded, plodding, plucky, plugging, preoccupied,
   purposeful, rapt, red-blooded, refractory, relentless, resistant,
   resolute, resolved, restive, retaining, retentive, rigid, ropy,
   secure, sedulous, self-adhesive, self-willed, serious, set,
   sincere, sinewy, single-minded, slabby, sleepless, slimy, slithery,
   slogging, spirited, spiritful, spunky, stable, stalwart, starchy,
   staunch, steadfast, steady, stickable, sticky, stiff, stiff-necked,
   stodgy, stout, stringy, strong, strong-minded, strong-willed,
   strongheaded, stubborn, sturdy, sulky, sullen, syrupy, tacky,
   thick, thickened, tight, tireless, tough, tough as leather,
   tremelloid, tremellose, true, unabating, uncompromising,
   unconquerable, uncooperative, undaunted, undiscouraged, undrooping,
   unfailing, unfaltering, unflagging, unflinching, unintermitting,
   uninterrupted, unnodding, unregenerate, unrelaxing, unrelenting,
   unremitting, unshakable, unshakeable, unshaken, unsleeping,
   unswerving, untiring, unwavering, unwearied, unwearying, unwinking,
   unyielding, utterly attentive, vigorous, viscid, viscose, viscous,
   weariless, wholehearted, willful, wiry

Tenacious >> T Words
Tenacious, definition of term: Tenacious
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