'arhat' originates from Sanskrit, specifically the word 'arhat' (also attested as 'arihant'), where the root 'arh' meant 'to be worthy' or 'to deserve'.

'arhat' entered English via Buddhist studies and translations in the 19th century; the word is also closely related to Pali 'arahant', which preserved the same basic form and sense before becoming the English 'arhat'.

Initially it meant 'a worthy one' (one deserving respect); over time the term became specialized in Buddhism to mean 'one who has attained nirvana' (a perfected, enlightened person).