'seizableness' originates from Modern English, specifically formed by adding the suffix '-ness' to the adjective 'seizable' (from 'seize' + '-able').

'seizable' descends from Middle English forms related to 'seisen'/'seise' (to take possession) and Old French 'saisir' (to seize); these in turn influenced the modern verb 'seize', from which 'seizable' and then 'seizableness' were formed.

Initially related to the action or result of taking possession ('to seize'), it came to be used as an adjective meaning 'able to be seized'; '-ness' later formed the abstract noun meaning 'the state or quality of being seizable'.