纖塵不染

see 一塵不染|一尘不染[yi1 chen2 bu4 ran3]

no; not so / (bound form) not; un-

to dye / to catch (a disease) / to acquire (bad habits etc) / to contaminate / to add color washes to a painting

fine / delicate / minute

speck of dust / fine dust

dust / dirt / earth