The word 'undefiled' is a layered negation built upon the concept of purity. Its core, the now-rare verb 'file' meaning to make foul, originates from Old English, carrying a sense of physical and moral corruption. The Latin prefix 'de-' was added to intensify this meaning, creating 'defile'—to pollute thoroughly. Finally, the Old English negative prefix 'un-' is applied to reverse the entire concept, resulting in a term that signifies a state of being completely free from any stain, corruption, or impurity, whether physical or spiritual.

Structure: un (not) + de (completely) + filed (made dirty) - un: A prefix of Germanic origin (Old English un-), meaning "not." It functions as a negative particle. - de: A prefix from Latin dē-, meaning "completely, thoroughly, down from." Here it intensifies the sense of the root. - filed: Derived from the verb defile, which itself comes from the obsolete verb file (to make dirty), of uncertain origin, possibly from Old English fȳlan (to befoul). The -ed suffix forms the past participle, used here adjectivally.