'inscrutable' originates from Late Latin, specifically the word 'inscrutabilis,' where 'in-' meant 'not' and 'scrutari' meant 'to search or examine.'

'inscrutabilis' transformed into the French word 'inscrutable,' and eventually became the modern English word 'inscrutable' through Middle English.

Initially, it meant 'not able to be searched or examined,' but over time it evolved into its current meaning of 'impossible to understand or interpret.'