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

serious \se"rious\, a. l. serius: cf. f. s'erieux, ll.
   seriosus.
   1. grave in manner or disposition; earnest; thoughtful;
      solemn; not light, gay, or volatile.
      1913 webster

            he is always serious, yet there is about his manner
            a graceful ease.                      --macaulay.
      1913 webster

   2. really intending what is said; being in earnest; not
      jesting or deceiving. --beaconsfield.
      1913 webster

   3. important; weighty; not trifling; grave.
      1913 webster

            the holy scriptures bring to our ears the most
            serious things in the world.          --young.
      1913 webster

   4. hence, giving rise to apprehension; attended with danger;
      as, a serious injury.
      1913 webster

   syn: grave; solemn; earnest; sedate; important; weighty. see
        grave.
        1913 webster -- se"riously, adv. --
        se"riousness, n.
        1913 webster
see also:
grave se"riously se"riousness 

[2] : WordNet (r) 2.0

serious
     adj 1: concerned with work or important matters rather than play or
            trivialities; "a serious student of history"; "a
            serious attempt to learn to ski"; "gave me a serious
            look"; "a serious young man"; "are you serious or
            joking?"; "don't be so serious" ant: frivolous
     2: of great consequence; "marriage is a serious matter"
     3: causing fear or anxiety by threatening great harm; "a
        dangerous operation"; "a grave situation"; "a grave
        illness"; "grievous bodily harm"; "a serious wound"; "a
        serious turn of events"; "a severe case of pneumonia"; "a
        life-threatening disease" syn: dangerous, grave, grievous,
         severe, life-threatening
     4: appealing to the mind; "good music"; "a serious book" syn:
        good
     5: completely lacking in playfulness syn: unplayful, sober
        ant: playful
     6: requiring effort or concentration; complex and not easy to
        answer or solve; "raised serious objections to the
        proposal"; "the plan has a serious flaw"
see also:
frivolous dangerous grave grievous severe life-threatening 
good unplayful sober playful 

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

189 moby thesaurus words for "serious":
   abandoned, acute, afire, alarming, ardent, arduous, austere,
   awe-inspiring, bad, bound, bound and determined, burning,
   businesslike, cogitative, cognitive, committed, comprehensive,
   concentrating, concentrative, conceptive, conceptual,
   conceptualized, consequential, considerable, contemplating,
   contemplative, critical, crucial, dangerous, dangersome, decided,
   decisive, decorous, dedicated, deep, definite, deliberating,
   deliberative, demure, determined, devoted, devout, difficult,
   dignified, dour, earnest, elevated, excogitating, exhaustive,
   explosive, faithful, fatal, fateful, fell, fervent, fervid, fiery,
   flaming, formal, formidable, fraught with danger, frowning, full,
   genuine, grand, grave, great, grievous, grim, grim-faced,
   grim-visaged, hearty, heated, heavy, honest, hot, hot-blooded,
   humorless, ideative, impassioned, important, imposing, in earnest,
   inspiring, intense, intent, intent on, introspective, irresistible,
   jeopardous, laborious, life-and-death, life-or-death, lofty,
   long-faced, loyal, main, majestic, major, maximum, meditating,
   meditative, menacing, mental, mighty, moderate, momentous, moving,
   museful, musing, nasty, no joke, no laughing matter, no-nonsense,
   noble, noetic, obstinate, on fire, operose, parlous, passionate,
   pensive, perfervid, periculous, perilous, persevering, persistent,
   plenary, poker-faced, pondering, portentous, powerful, precarious,
   prehensive, pressing, purposeful, red-hot, reflecting, reflective,
   relentless, resolute, resolved, ruminant, ruminating, ruminative,
   sedate, serious-minded, severe, significant, sincere,
   single-minded, sober, sober-minded, sobersided, solemn, somber,
   speculative, spirited, staid, stately, steady, stern, stone-faced,
   straight-faced, straightforward, strenuous, strong, sublime,
   temperate, tenacious, thinking, thought, thoughtful, threatening,
   total, tough, ugly, unamusing, unfunny, unsmiling, urgent,
   vehement, vital, warm, weighty, white-hot, wholehearted, wistful,
   zealous

Serious >> S Words
Serious, definition of term: Serious
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