atone
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verb no object
make amends or reparation:
⦅かたく⦆ 【罪・過失などの】償い[罪滅ぼし]をする «for»
e.g. he was being helpful, to atone for his past mistakes.
ORIGIN
Middle English (originally in the sense ‘make or become united or reconciled’, rare before the 16th century): from at one in early use; later by back-formation from atonement.