The definition of an alibi is an excuse used by a person when they’re trying to avoid getting into trouble, so they say they were somewhere they weren’t.(noun)
The definition of alibi is the act of saying that someone was with you instead of where someone is accused of being, either as a defense for an accusation or as a way to avoid getting into trouble.(verb)
When a wife says her husband was at home when the murder occurred, it is an example of alibi.
See alibi in Webster's New World College Dictionary
See alibi in American Heritage Dictionary 4
noun pl. al·i·bis
Origin: Latin, elsewhere
Origin: , from alius, other (on the model of ibi, there); see al-1 in Indo-European roots. Usage Note: When used as a noun, alibi in its nonlegal sense of “an excuse” is acceptable in written usage to almost half of the Usage Panel. As a verb (they never alibi), it is unacceptable in written usage to a large majority of the Panel.
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