'stibnous' originates from Latin, specifically the word 'stibium', where 'stibium' meant 'antimony'.

'stibnous' developed from the New Latin/Greek stem 'stib-' (from 'stibium') combined with the English adjectival suffix '-ous', resulting in the modern English adjective 'stibnous'.

Initially, it meant 'of or relating to antimony', and over time it has retained this specific chemical sense of 'containing or characteristic of antimony' (often indicating the lower oxidation state).