noun, na-adjective, noun which may take the genitive case particle 'no'
pure and unadulterated; pure in heart; simplehearted
A yojijukugo describing something completely pure, without mixture or impurity; can refer to substances, character, or motives. Literary and somewhat formal.
His pure and unadulterated faith moved many people.
この水は純一無雑で、一切の不純物を含まない。
This water is pure and unadulterated, containing no impurities whatsoever.
純粋 is the common word for 'pure' in everyday contexts. 純一無雑 is a more emphatic, literary yojijukugo emphasizing absolute purity without any mixture.
純真 means 'pure and innocent', often used for a person's heart or character. 純一無雑 can also describe purity of heart but with a stronger nuance of being untainted by any foreign element.
A yojijukugo composed of 純 (pure), 一 (one, single), 無 (without), and 雑 (miscellaneous, impurity). The combination literally means 'pure, single, without mixture', emphasizing absolute purity. The exact historical origin is uncertain, but it follows a common pattern of four-character idiomatic compounds in literary Chinese and Japanese.