'appointable' originates from English, specifically formed from the verb 'appoint' + the suffix '-able', where 'appoint' comes from Old French 'apointer' (ultimately from Latin roots) and the suffix '-able' comes from Latin '-abilis' meaning 'capable of'.

'appoint' changed from Old French word 'apointer' (and Middle English 'appointen') and eventually became the modern English verb 'appoint'; the productive adjectival suffix '-able' was then added to create 'appointable'.

Initially the root 'appoint' meant 'to fix, arrange, or assign' (from Old French usage), and over time combining it with '-able' produced the modern sense 'capable of being assigned or given an office/position'.