'self-confident' originates from the combination of 'self' and 'confident', where 'self' refers to one's own person and 'confident' comes from Latin 'confidere', meaning 'to trust'.

'confidere' transformed into the Old French word 'confident', and eventually became the modern English word 'confident', combined with 'self' to form 'self-confident'.

Initially, it meant 'trusting in oneself', and this meaning has largely remained the same in modern usage.