the word 'unidentifiable' is a modern english formation built upon the established verb 'identify'. the core verb 'identify' entered english in the 17th century from the medieval latin 'identificare', meaning 'to make the same', which itself combines 'idem' (same) and 'facere' (to make). to this verb, the suffix '-able' (capable of being) was added to create the adjective 'identifiable'. finally, the old english/germanic negative prefix 'un-' was attached, following a common pattern in english word formation to create opposites. thus, the literal morphemic construction 'not capable of being made the same' logically evolved into the modern abstract meaning of something that cannot be recognized or named.

Structure: un (not) + identifi (to identify) + able (capable of) un: a prefix of germanic origin, used to give a negative or opposite force to adjectives and their derivatives. identifi: a substring derived from the verb 'identify', which originates from late latin 'identificare', from latin 'idem' (same) + 'facere' (to make). able: a suffix of latin origin (via old french), from latin '-abilis', meaning 'capable of, fit for, tending to'.