layman's eyes; untrained eye
Refers to the perspective or judgment of an ordinary person without specialized knowledge, often contrasted with expert or professional insight. Somewhat literary or formal.
It is such exquisite workmanship that an untrained eye cannot tell the difference.
To a layman's eyes, his painting might look like mere scribbles.
Compound of 凡 (ordinary, common) and 眼 (eye). The exact historical origin is uncertain, but the word is formed from kanji meaning 'ordinary eye'.