watertight alibi
1
4.4
- noun
- /ˈwɔːtərˌtaɪt ˈælɪbaɪ/
:
coartada irrefutable
- In court, she presented a watertight alibi that convinced everyone of her innocence.
Examples
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The detective was impressed by the suspect's watertight alibi, which proved he was miles away during the crime.
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Now I am well aware, Monsieur Poirot, that in your world when a murder takes place everyone automatically comes up with a watertight alibi.
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With a watertight alibi, he confidently answered the police's questions about his whereabouts.
Synonyms
5
3.8
A strong proof that someone was somewhere else when a crime happened
2
5.8
Very strong proof that someone was somewhere else and cannot be proved wrong
How Strong
Surface Forms
Morphology
The adjective 'watertight' (completely sealed/secure) combined with 'alibi' (proof of absence) yields a compositional meaning: an alibi that cannot be pierced or disproved. The metaphorical extension of 'watertight' to mean 'unassailable' is a common and transparent adjectival modifier, so a B1 learner who knows both constituents should be able to infer the MWE's meaning.
Etymology
Watertight alibi comes from the simple image of something that is watertight — a sealed container where no water can get in — and an alibi is proof you were somewhere else. So a watertight alibi means a statement or proof that is 'impossible to disprove'.