the word 'unavoidably' is built upon the core verb 'avoid', which entered english from anglo-french 'avoider', itself derived from the vulgar latin 'avoidare', meaning "to empty out". the prefix 'un-', of old english origin, is added to negate the possibility implied by the suffix '-able', which comes from the latin '-abilis', denoting capability. therefore, the literal construction is "in a manner that cannot be made empty of or escaped from". over time, the sense evolved from the physical act of emptying or departing to the more abstract notion of being impossible to prevent or evade, solidifying its modern adverbial meaning describing an inevitable manner.

Structure: un (not) + avoid (prevent) + ably (in a manner of) - un: a prefix of germanic origin, meaning "not". - avoid: from anglo-french 'avoider', meaning "to clear out, depart, shun". the core sense is "to prevent or keep away from". - ably: an adverbial suffix from latin '-abilis' via old french '-able' and '-ably', meaning "in a manner that can be [verb]ed".