'incertidumbre' originates from Latin, specifically the word 'incertitudo', where the prefix 'in-' meant 'not' and 'certus' meant 'certain'.

'incertitudo' passed through Medieval Latin and Old Spanish forms (e.g. medieval 'incertidumbre'/'incertidut') and eventually became the modern Spanish 'incertidumbre'.

Initially it referred to the abstract condition of being 'not certain' (from Latin), and this basic sense has been retained while extending to specialized senses like economic or political unpredictability.