'ruinability' originates from Latin, specifically the word 'ruina' (from the verb 'ruere'), where 'ruere' meant 'to fall' or 'to collapse'; the suffix '-ability' comes from Latin '-abilis' via Anglo-French, meaning 'able to be'.

'ruina' changed into Old French 'ruine' and then into Middle English 'ruin'; in Modern English the noun 'ruin' took the productive suffix '-ability' to form 'ruinability'.

Initially it was associated with physical 'collapse' or 'falling down'; over time the sense broadened to the abstract quality of 'being able to be ruined or damaged'.