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

conscientious \con`scien"tious\, a. cf. f. consciencieux, ll.
   conscientiosus.
   1. influenced by conscience; governed by a strict regard to
      the dictates of conscience, or by the known or supposed
      rules of right and wrong; -- said of a person.
      1913 webster

            the advice of wise and conscientious men.
                                                  --prescott.
      1913 webster

   2. characterized by a regard to conscience; conformed to the
      dictates of conscience; -- said of actions.
      1913 webster

            a holy and conscientious course.      --abp.
                                                  tillotson.

   syn: scrupulous; exact; faithful; just; upright.
        1913 webster

[2] : WordNet (r) 2.0

conscientious
     adj 1: characterized by extreme care and great effort;
            "conscientious application to the work at hand";
            "painstaking research"; "scrupulous attention to
            details" syn: painstaking, scrupulous
     2: guided by or in accordance with conscience or sense of right
        and wrong; "a conscientious decision to speak out about
        injustice" ant: unconscientious
see also:
painstaking scrupulous unconscientious 

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

97 moby thesaurus words for "conscientious":
   accurate, active, attentive, careful, cautious, censorious, choicy,
   choosy, circumspect, close, compliant, conforming, conscionable,
   constant, correct, critical, deferential, delicate, demanding,
   detailed, devoted, devout, diligent, discreet, discriminating,
   discriminative, duteous, dutiful, ethical, exact, exacting,
   exigent, exquisite, fair, faithful, fastidious, fine, finical,
   finicking, finicky, fussy, heedful, high-minded, honest, honorable,
   incorruptible, just, loyal, meticulous, mindful, minute, moral,
   narrow, nice, obedient, observant, overconscientious,
   overscrupulous, painstaking, particular, perfectionistic, picky,
   politic, practicing, precise, precisianistic, precisionistic,
   priggish, principled, prudent, prudish, punctilious, punctual,
   puristic, puritanic, refined, regardful, religious, respectful,
   responsible, right, right-minded, righteous, rigid, rigorous,
   scrupulous, scrutinizing, selective, sensitive, serious, strict,
   subtle, tender-conscienced, thorough, true, upright, upstanding

Conscientious >> C Words
Conscientious, definition of term: Conscientious
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Conscientious O >> C Words
Conscientious O, definition of term: Conscientious O
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