'unstably-formed' originates from the combination of 'unstable' and 'formed', where 'un-' is a prefix meaning 'not', 'stable' comes from Latin 'stabilis' meaning 'firm', and 'formed' is derived from Latin 'formare' meaning 'to shape'.

'unstable' changed from the Old French word 'unstable' and eventually became the modern English word 'unstable'.

Initially, 'unstable' meant 'not firm or fixed', and this meaning has largely remained the same in modern usage.