'uncollectible' originates from the prefix 'un-' meaning 'not' and the word 'collectible', which comes from the Latin 'collectus', the past participle of 'colligere', meaning 'to gather together'.

'collectus' transformed into the Old French word 'collecter', and eventually became the modern English word 'collectible'. The prefix 'un-' was added to form 'uncollectible'.

Initially, 'collectible' meant 'able to be gathered', but with the prefix 'un-', it evolved to mean 'not able to be collected', especially in financial contexts.