'pernicious' originates from Latin, specifically the word 'perniciosus,' where 'per-' meant 'through' and 'nex' meant 'violent death.'

'perniciosus' transformed into the Old French word 'pernicieux,' and eventually became the modern English word 'pernicious' through Middle English.

Initially, it meant 'leading to death,' but over time it evolved into its current meaning of 'harmful or damaging.'