'bairagi' originates from Hindi/Urdu, specifically the word 'bairāgī', where the form reflects Sanskrit roots: 'vi-' (apart, without) and 'rāga' (passion, attachment).

'bairagi' changed from Sanskrit 'vairāgya'/'vairāgika' into Prakrit and then Hindi/Urdu 'bairāgī', and eventually entered English as 'bairagi' through contact with South Asian languages.

Initially it referred to the state of dispassion or 'absence of attachment' (vairāgya); over time it came to denote specifically a religious renunciate or ascetic in Hindu practice.