'backboneless' originates from English, specifically from the compound 'backbone' and the suffix '-less', where 'back' meant 'back', 'bone' meant 'bone', and '-less' meant 'without'.

'backboneless' was formed in Modern English by attaching the suffix '-less' to 'backbone' (the element 'backbone' itself traces to Old English 'bæcbān' from 'bæc' = 'back' + 'bān' = 'bone'), yielding the adjective 'backboneless'.

Initially the elements referred to the physical 'spinal column' and 'without'; over time the compound has been used both for a literal absence of a spine and figuratively to describe someone 'lacking courage or resolve', similar to 'spineless'.