'repel' originates from Latin, specifically the word 'repellere', where 're-' meant 'back' and 'pellere' meant 'to drive'.

'repellere' passed into Late Latin and Old French forms and then into Middle English (e.g. Middle English 'repellen'), eventually becoming the modern English word 'repel'.

Initially it meant 'to drive back' or 'push away', and over time the core sense of 'driving away' remained while extended senses like 'cause disgust' developed.