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

weighty \weight"y\, a. compar. weightier; superl.
   weightiest.
   1913 webster
   1. having weight; heavy; ponderous; as, a weighty body.
      1913 webster

   2. adapted to turn the balance in the mind, or to convince;
      important; forcible; serious; momentous. "for sundry
      weighty reasons." --shak.
      1913 webster

            let me have your advice in a weighty affair.
                                                  --swift.
      1913 webster

   3. rigorous; severe; afflictive. r. "attend our weightier
      judgment." --shak.
      1913 webster

   syn: heavy; ponderous; burdensome; onerous; forcible;
        momentous; efficacious; impressive; cogent.
        1913 webster
see also:
weightier weightiest 

[2] : WordNet (r) 2.0

weighty
     adj 1: having relatively great weight; heavy; "a weighty load"; "a
            weighty package" ant: weightless
     2: of great gravity or crucial import; requiring serious
        thought; "grave responsibilities"; "faced a grave decision
        in a time of crisis"; "a grievous fault"; "heavy matters
        of state"; "the weighty matters to be discussed at the
        peace conference" syn: grave, grievous, heavy
     3: weighing heavily on the spirit; causing anxiety or worry;
        "weighty problems"
     4: excessively fat; "a weighty man" syn: corpulent, obese,
         rotund
     5: powerfully persuasive; "a cogent argument"; "a telling
        presentation"; "a weighty argument" syn: cogent, telling
     also: weightiest, weightier
see also:
weightless grave grievous heavy corpulent obese 
rotund cogent telling weightiest weightier 

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

224 moby thesaurus words for "weighty":
   gargantuan, absolute, adducible, admissible, amplitudinous,
   ascendant, astronomical, attestative, attestive, authentic,
   authoritarian, authoritative, authorized, autocratic,
   awe-inspiring, awesome, based on, big, binding, boundless, bulky,
   burdensome, certain, charismatic, charming, circumstantial,
   clothed with authority, cogent, colossal, commanding, competent,
   conclusive, consequential, considerable, consistent, controlling,
   convincing, corpulent, cosmic, cumbersome, cumbrous, cumulative,
   damning, decisive, decorous, demanding, demure, determinative,
   dignified, documentary, documented, dominant, duly constituted,
   earnest, effective, effectual, efficacious, elevated, eminent,
   empowered, enchanting, enormous, estimable, evidential,
   evidentiary, ex officio, ex parte, exacting, exhausting, exigent,
   extensive, eye-witness, factual, fat, fatal, fateful, final,
   firsthand, fleshy, formal, formidable, founded on, frowning,
   galactic, gigantic, good, governing, grand, grave, great, grievous,
   grim, grim-faced, grim-visaged, grinding, gross, grounded on,
   harsh, hearsay, heavy, heavyweight, hefty, hegemonic, hegemonistic,
   huge, immeasurable, immense, imperative, implicit, important,
   imposing, incontrovertible, indicative, indisputable, infinite,
   influential, inspiring, irrefutable, irresistible, just, king-size,
   large, lawful, leaden, leading, legal, legitimate, lofty, logical,
   long-faced, magnetic, majestic, mammoth, massive, massy, material,
   meaningful, mighty, momentous, monocratic, monster, monstrous,
   monumental, mountainous, moving, no-nonsense, noble, nuncupative,
   obese, official, onerous, oppressive, outsize, overburdensome,
   overgrown, overweight, overwhelming, personable, persuasive,
   ponderous, portentous, portly, potent, powerful, preeminent,
   prestigious, presumptive, probative, prodigious, prominent,
   puissant, ranking, reliable, reputable, ruling, sedate,
   self-consistent, senior, serious, severe, significant, sizable,
   sober, sober-minded, sobersided, solemn, solid, somber, sound,
   spacious, staid, stately, stone-faced, stout, straight-faced,
   strong, stupendous, suasive, sublime, substantial, sufficient,
   suggestive, superincumbent, superior, supreme, sure, symptomatic,
   taxing, telling, thoughtful, titanic, totalitarian, tough,
   tremendous, tyrannous, unsmiling, valid, vast, voluminous, wearing,
   wearying, well-founded, well-grounded, winning

Weighty >> W Words
Weighty, definition of term: Weighty
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