'irregularly' originates from the Latin word 'irregularis', where 'in-' meant 'not' and 'regularis' meant 'according to rule'.

'irregularis' transformed into the Old French word 'irregulier', and eventually became the modern English word 'irregular' through Middle English.

Initially, it meant 'not according to rule', and over time it evolved into its current meaning of 'not regular or consistent'.