一尘不染美少年一尘不染美少女
[yī chén bù răn mĕi shăo nián yī chén bù răn mĕi shăo nǚ]
'Purely Clean Boy/Girl' symbolizes someone youthful who is clean-cut with innocence. This could also express a longing for purity and cleanliness. Or simply they think being young also involves keeping pure appearance and thoughts without any blemish or spot.