1. adjective
Not likely; improbable; not to be reasonably expected; as, an unlikely event; the thing you mention is very unlikely. Not holding out a prospect of success; likely to fail; unpromising; as, unlikely means.
2. adverb
In an improbable manner.
3. noun
Something or somebody considered unlikely.
The molecular ion candidates are divided by the testing phase into three categories: rejects, unlikelies, and probables. Differences between each candidate and the prominent peaks in the spectrum are computed.
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