'backbonelessness' originates from English, specifically built from the noun 'backbone' plus the adjective-forming suffix '-less' and the nominalizing suffix '-ness'.

'backbone' originates from Old English elements 'bæc' meaning 'back' and 'bān' meaning 'bone'; the suffixes '-less' (from Old English 'lēas', meaning 'free from') and '-ness' (from Old English '-nes(s)e') were later combined to form abstract nouns such as 'backbonelessness'.

Initially the components referred to the literal anatomical idea 'without a backbone', but over time the compound has also acquired a figurative meaning of 'lacking courage or firmness'.