'slip-up' originates from English, specifically a combination of the verb 'slip' and the particle 'up', where 'slip' originally meant 'to glide or slide' and 'up' functions here as a particle forming a verbal/adjectival compound.

'slip' comes from Old English 'slipan' meaning 'to glide, move smoothly'; it passed into Middle English as 'slippen' and later became modern English 'slip'. The compound 'slip-up' developed in later English as a colloquial formation combining 'slip' + 'up' to mean an error rather than a physical slide.

Initially, 'slip' referred mainly to physical sliding or gliding; over time the sense broadened figuratively to include 'making an error' and 'slip-up' came to mean 'a small mistake' in modern usage.