Source : Webster's Revised Unabridged Dictionary (1913)

Unlikely \Un*like"ly\, a.
   1. Not likely; improbable; not to be reasonably expected; as,
      an unlikely event; the thing you mention is very unlikely.

   2. Not holding out a prospect of success; likely to fail;
      unpromising; as, unlikely means. --Hooker.

   3. Not such as to inspire liking; unattractive; disagreeable.
      [Obs.] ``The unlikely eld of me.'' --Chaucer.

Unlikely \Un*like"ly\, adv.
   In an unlikely manner.

Source : WordNet®

unlikely
     adj 1: not likely to be true or to occur or to have occurred;
            "legislation on the question is highly unlikely"; "an
            improbable event" [syn: {improbable}] [ant: {probable}]
     2: has little chance of being the case or coming about; "an
        unlikely story"; "an unlikely candidate for reelection";
        "a butcher is unlikely to preach vegetarianism" [ant: {likely}]
     3: having a probability to low to inspire belief [syn: {improbable},
         {unbelievable}, {unconvincing}]