the.com/stain

means A discoloration or mark left on a surface, usually one that's hard to remove and unwelcome — or, figuratively, a lasting blot on a reputation.

from From Middle English 'steinen,' likely shortened from Old French 'desteindre' meaning to remove color or take away dye (from 'des-' off + 'teindre' to dye, ultimately from Latin 'tingere,' to dip or color). There may also be influence from Old Norse 'steina,' to paint. The irony is built in: a word rooted in coloring and dyeing came to mean color landing exactly where you didn't want it.