Available Definitions:
1) a. - Not likely; improbable; not to be reasonably expected; as, an unlikely event; the thing you mention is very unlikely.
2) a. - Not holding out a prospect of success; likely to fail; unpromising; as, unlikely means.
3) a. - Not such as to inspire liking; unattractive; disagreeable.
4) adv. - In an unlikely manner.