the word 'unreliable' is a modern english formation built upon the positive adjective 'reliable'. the core morpheme 'reli' traces back to the latin verb 'religare', meaning "to bind fast", which conceptually evolved into the sense of firm attachment or dependence. the suffix '-able' was added to create the meaning "capable of being depended upon". finally, the old english negative prefix 'un-' is attached to reverse the meaning, resulting in the modern sense of "not capable of being bound to or depended upon", effectively describing something or someone that cannot be trusted.

Structure: un (not) + reli (depend) + able (capable of) - un: a prefix of germanic origin (old english) meaning "not", used to form negatives. - reli: a morpheme derived from the verb 'rely', which originates from old french 'relier' (to fasten, attach), from latin 'religare' (to bind fast). - able: a suffix of latin origin (via old french) meaning "capable of, fit for", used to form adjectives.