'atoner' originates from English, specifically from the verb 'atone' plus the agentive suffix '-er', where 'atone' meant 'to bring to oneness or reconciliation' and '-er' denotes 'one who does'.

'atoner' changed from the verb phrase and verb 'atone' (Middle English 'at one' meaning 'in agreement' or 'reconciled') with the addition of the agent suffix '-er' to form the noun 'atoner'. The elements 'at' and 'one' go back to Old English 'æt' and 'ān'.

Initially, 'atone' meant 'to be at one' (to agree or be reconciled); over time it evolved to mean 'to make amends' or 'to reconcile by reparative action', and 'atoner' came to mean 'one who makes amends'.