un·cer·tain /ˌʌnˈsɚ/
 (a.)不確定的,無常的,不確信的,不可預測的
 uncertain
 不確定
 Un·cer·tain a.
 1. Not certain; not having certain knowledge; not assured in mind; distrustful.
    Man, without the protection of a superior Being, . . . is uncertain of everything that he hopes for.   --Tillotson.
 2. Irresolute; inconsonant; variable; untrustworthy; as, an uncertain person; an uncertain breeze.
 O woman! in our hours of ease,
 Uncertain, coy, and hard to please!   --Sir W. Scott.
 3. Questionable; equivocal; indefinite; problematical. “The fashion of uncertain evils.”
    From certain dangers to uncertain praise.   --Dryden.
 4. Not sure; liable to fall or err; fallible.
    Soon bent his bow, uncertain in his aim.   --Dryden.
    Whistling slings dismissed the uncertain stone.   --Gay.
 Syn: -- See Precarious.
 Un·cer·tain, v. t.  To make uncertain. [Obs.]
 ◄ ►
 uncertain
      adj 1: lacking or indicating lack of confidence or assurance;
             "uncertain of his convictions"; "unsure of himself and
             his future"; "moving with uncertain (or unsure)
             steps"; "an uncertain smile"; "touched the ornaments
             with uncertain fingers" [syn: unsure, incertain]
             [ant: certain(p), certain(p)]
      2: not established beyond doubt; still undecided or unknown;
         "an uncertain future"; "a manuscript of uncertain origin";
         "plans are still uncertain"; "changes of great if
         uncertain consquences"; "without further evidence his
         story must remain uncertain" [ant: certain(p)]
      3: not established or confirmed; "his doom is as yet unsealed"
         [syn: unsealed] [ant: sealed]
      4: not firm or secure; "balancing three boxes in an uncertain
         pile"
      5: not certain to occur; not inevitable; "everything is
         uncertain about the army"; "the issue is uncertain" [ant:
         certain]
      6: subject to change; "a changeable climate"; "the weather is
         uncertain"; "unsettled weather with rain and hail and
         sunshine coming one right after the other" [syn: changeable,
          unsettled]
      7: not safe from danger or mishap; "faced an uncertain future";
         "an unsure existence" [syn: unsure]
      8: not consistent or dependable; "an uncertain recollection of
         events"; "a gun with a rather uncertain trigger"
      9: ambiguous (especially in the negative); "she spoke in no
         uncertain terms"