The Collaborative International Dictionary of English v.0.48:

Stanch \Stanch\ (st[.a]nch), v. t. [imp. & p. p. Stanched
   (st[.a]ncht); p. pr. & vb. n. Stanching.] [OF. estanchier,
   F. ['e]tancher to stop a liquid from flowing; akin to Pr.,
   Sp., & Pg. estancar, It. stancare to weary, LL. stancare,
   stagnare, to stanch, fr. L. stagnare to be or make stagnant.
   See Stagnate.]
   1. To stop the flowing of, as blood; to check; also, to stop
      the flowing of blood from; as, to stanch a wound. [Written
      also staunch.]
      [1913 Webster]

            Iron or a stone laid to the neck doth stanch the
            bleeding of the nose.                 --Bacon.
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   2. To extinguish; to quench, as fire or thirst. [Obs.]
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Stanch \Stanch\, a. [Compar. Stancher (-[~e]r); superl.
   Stanchest.] [From Stanch, v. t., and hence literally
   signifying, stopped or stayed; cf. Sp. estanco stopped,
   tight, not leaky, as a ship. See Stanch, v. t.] [Written
   also staunch.]
   1. Strong and tight; sound; firm; as, a stanch ship.
      [1913 Webster]

            One of the closets is parqueted with plain deal, set
            in diamond, exceeding stanch and pretty. --Evelyn.
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   2. Firm in principle; constant and zealous; loyal; hearty;
      steady; steadfast; as, a stanch churchman; a stanch friend
      or adherent. --V. Knox.
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            In politics I hear you 're stanch.    --Prior.
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   3. Close; secret; private. [Obs.]
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            This is to be kept stanch.            --Locke.
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The Collaborative International Dictionary of English v.0.48:

Staunch \Staunch\ (st[aum]nch), Staunchly \Staunch"ly\,
Staunchness \Staunch"ness\, etc.
   See Stanch, Stanchly, etc.
   [1913 Webster]

WordNet (r) 3.0 (2006):

staunch
    adj 1: firm and dependable especially in loyalty; "a steadfast
           ally"; "a staunch defender of free speech"; "unswerving
           devotion"; "unswerving allegiance" [syn: steadfast,
           staunch, unswerving]
    v 1: stop the flow of a liquid; "staunch the blood flow"; "stem
         the tide" [syn: stem, stanch, staunch, halt]

Moby Thesaurus II by Grady Ward, 1.0:

118 Moby Thesaurus words for "staunch":
   Sabbatarian, airtight, ardent, bigoted, calculable, close,
   committed, compact, consistent, constant, creedbound, dedicated,
   dependable, devoted, dogmatic, dustproof, dusttight, evangelical,
   faithful, faithworthy, fast, firm, firm as Gibraltar, fixed,
   flinty, fundamentalist, gasproof, gastight, hermetic,
   hermetically sealed, hidebound, hyperorthodox, immovable,
   inflexible, infrangible, invincible, liege, lightproof, lighttight,
   literalist, literalistic, long-lasting, loyal, made of iron,
   marble-constant, oilproof, oiltight, precisianist, precisianistic,
   predictable, purist, puristic, puritanical, rainproof, raintight,
   reliable, resolute, rigid, rugged, sealed, seaworthy, secure, set,
   settled, shut fast, smokeproof, smoketight, snug, solid, sot,
   sound, stable, steadfast, steady, steely, stormproof, stormtight,
   stout, straitlaced, strict, strong, sturdy, substantial, sure,
   surefire, tested, tight, tough, tried, tried and true, true,
   true-blue, trusted, trustworthy, trusty, unbending, unbreakable,
   undeflectable, undeviating, unfailing, unfaltering, unflappable,
   unflinching, unshaken, unshrinking, unswerving, unwavering,
   unyielding, water-repellant, waterproof, watertight, well-built,
   well-constructed, well-founded, well-grounded, well-made,
   windproof, windtight