'inscrutability' originates from Latin, specifically related to the verb 'scrutari', where the root 'scrut-' meant 'to search' and the prefix 'in-' meant 'not'.

'inscrutability' developed via Latin and Medieval Latin forms (e.g. 'inscrutabilis' / 'inscrutabilitas') and the adjective 'inscrutable' before being formed into the English noun 'inscrutability' by adding the suffix '-ity' in later English.

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