'cautioner' originates from Latin, specifically the word 'cautio,' where 'cavēre' meant 'to beware' or 'to be cautious.'

'cautio' passed into Old French as 'caution' and into Middle English as 'caution'; the agentive English suffix '-er' was later added to form the noun 'cautioner' (literally 'one who gives caution' or 'one who provides security').

Initially related to the Latin sense of 'taking care' or providing 'security,' the term developed to denote both a person who gives a formal warning and a person who acts as a guarantor; the legal sense ('guarantor') is especially prominent in historical and regional usage.