Here's a breakdown of its etymology:
* Un-: This prefix, meaning "not" or "the opposite of", has Germanic origins.
* Mistakable: This word is formed by adding the "-able" suffix to "mistake".
* Mistake: This word has a complex etymology, ultimately deriving from the Old French word "mesprendre", which means "to take wrongly" or "to misunderstand".
Therefore, the full etymology of "unmistakable" can be traced back to the Old French "mesprendre", signifying the opposite of being able to be taken wrongly or misunderstood.