'rejectability' originates from Latin, specifically the verb 'reicere' (through Old French), where 're-' meant 'back' and 'iacere' (or 'iacere'/'iacio') meant 'to throw'.

'rejectability' developed in Modern English by adding the suffix '-ability' to the adjective 'rejectable' (from Middle English/Old French 'rejeter' < Latin 'reicere'), producing the noun meaning 'the quality of being rejectable'.

Initially related to the Latin idea 'to throw back', the sense evolved into the modern abstract noun meaning 'the quality or state of being able to be rejected'.