Other forms: alibis
An alibi is proof that you were somewhere else when a crime was committed. A cast-iron alibi, provide an alibi, his alibi held up.
It is a defence rather than a denial: an alibi does not say you did not do it, it says you could not have. That is why alibis are checked rather than believed. In loose everyday use it has drifted to mean any excuse, which lawyers object to. Note that the plural is alibis, and that providing a false alibi is itself an offence.
1nounalibiProof that you were somewhere else when a crime happened.
“His alibi was four people and a receipt.”
alibi is a legal defence.
Latin alibi means elsewhere — ali-, other, plus ibi, there. The word entered English law directly from Latin as a plea, and it is one of very few Latin adverbs to become an ordinary English noun.
French
alibi
Latin
alibī — elsewhere, at another place
English, today
alibi
From the 18th century, from Latin alibī (“elsewhere, at another place”). Probably after French alibi, which has this use since the late 14th century.
Etymology from Wiktionary, CC BY-SA