self-evident

from WordNet (r) 3.0 (2006)

self-evident
    adj 1: evident without proof or argument; "an axiomatic truth";
           "we hold these truths to be self-evident" [syn:
           {axiomatic}, {self-evident}, {taken for granted(p)}]

from The Collaborative International Dictionary of English v.0.48

Self-evident \Self`-ev"i*dent\, a.
   Evident without proof or reasoning; producing certainty or
   conviction upon a bare presentation to the mind; as, a
   self-evident proposition or truth. -- {Self`-ev"i*dent*ly},
   adv.
   [1913 Webster]

from The Devil's Dictionary (1881-1906)

SELF-EVIDENT, adj.  Evident to one's self and to nobody else.

from Moby Thesaurus II by Grady Ward, 1.0

59 Moby Thesaurus words for "self-evident":
      absolute, actual, admitting no question, apparent, axiomatic,
      clear, clear as crystal, clear-cut, confirmable, crystal-clear,
      definite, demonstrable, demonstratable, discernible, distinct,
      evident, explicit, express, factual, historical, inappealable,
      incontestable, incontrovertible, indisputable, indubitable,
      inescapable, irrefragable, irrefutable, manifest, noticeable,
      observable, obvious, open-and-shut, palpable, patent, perceivable,
      perceptible, perspicuous, plain, plain as day, provable,
      proverbial, real, seeable, self-explaining, self-explanatory,
      tangible, testable, to be seen, true, unanswerable, unconfutable,
      undeniable, unimpeachable, unmistakable, unquestionable,
      unrefutable, verifiable, visible