stain 
(stān)
(stān)v. stained, stain·ing, stains
v.tr.
1. To discolor, soil, or spot: The spilled juice stained the carpet.
2. To bring into disrepute; taint or tarnish: The scandal stained the mayor's reputation.
3. To change the color of (a piece of wood, for example) by applying a stain.
4. To treat (a specimen for the microscope) with a reagent or dye in order to identify cell or tissue structures or microorganisms.
v.intr.
To produce or receive discolorations: upholstery that stains easily.
n.
1. A discolored or soiled spot or smudge: a stain that was difficult to scrub out.
2. A diminishment of one's moral character or good reputation by being associated with something disgraceful.
3. A liquid substance applied especially to wood that penetrates the surface and imparts a rich color.
4. A reagent or dye used for staining microscopic specimens.
[Middle English steinen, partly from Old French desteindre, desteign-, to deprive of color (des-, dis- + teindre, to dye, from Latin tingere), and partly from Old Norse steina, to paint.]
staina·ble adj.
stainer n.
Synonyms: stain, blot1, brand, stigma, taint
These nouns denote a mark of discredit or disgrace, as on one's good name: a stain on his honor; a blot on an otherwise clean police record; the brand of cowardice; the stigma of ignominious defeat; the taint of political corruption.
These nouns denote a mark of discredit or disgrace, as on one's good name: a stain on his honor; a blot on an otherwise clean police record; the brand of cowardice; the stigma of ignominious defeat; the taint of political corruption.