'insomniac' originates from Latin, specifically the word 'insomnis,' where 'in-' meant 'not' and 'somnus' meant 'sleep.'

'insomnis' transformed into the French word 'insomnie,' and eventually became the modern English word 'insomnia,' from which 'insomniac' is derived.

Initially, it meant 'without sleep,' and this meaning has largely remained the same in modern usage.