'observant' originates from Latin, specifically the word 'observantem,' where 'ob-' meant 'toward' and 'servare' meant 'to watch or keep.'

'observantem' transformed into the Old French word 'observant,' and eventually became the modern English word 'observant' through Middle English.

Initially, it meant 'to watch or keep,' but over time it evolved into its current meaning of 'quick to notice or perceive things.'