'unsuitably-separated' originates from the combination of 'unsuitable' and 'separated', where 'un-' is a prefix meaning 'not', 'suitable' means 'appropriate', and 'separated' means 'divided or disconnected'.

The word 'unsuitably-separated' evolved from the combination of 'unsuitable' and 'separated', which have been used in English since the Middle Ages.

Initially, it meant 'not appropriately divided', and this meaning has largely remained the same in modern usage.