1. [adj]  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"
2. [adj]  not likely to be true or to occur or to have occurred; "legislation on the question is highly unlikely"; "an improbable event"
3. [adj]  having a probability to low to inspire belief

UNLIKELY is a 8 letter word that starts with U.

1. \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.
   
   

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