'self-important' originates from the combination of 'self' and 'important', where 'self' refers to one's own person and 'important' means having great significance or value.

'self-important' evolved from the Middle English word 'important', which was derived from the Latin 'importare', meaning 'to bring in'.

Initially, it meant 'having significance', but over time it evolved into its current meaning of 'having an exaggerated sense of one's own value'.