'definiteness' originates from Latin, specifically the word 'definitus,' where 'de-' meant 'down' and 'finire' meant 'to limit or end.'

'definitus' transformed into the French word 'défini,' and eventually became the modern English word 'definite' through Middle English.

Initially, it meant 'to limit or end,' but over time it evolved into its current meaning of 'clear and unambiguous.'