'loosely-built' originates from the combination of 'loose' and 'built', where 'loose' meant 'not tight' and 'built' referred to 'constructed'.

'loose' changed from Old English 'lēas' meaning 'free from' and 'built' from Old English 'byldan', eventually forming the modern English term 'loosely-built'.

Initially, it meant 'constructed in a loose manner', and this meaning has largely remained the same in modern usage.