Open English Wordnet
Nouns
(n)stain(microscopy) a dye or other coloring material that is used in microscopy to make structures visible (n)mark, stigma, brand, staina symbol of disgrace or infamy“And the Lord set a mark upon Cain” (The Bible, Genesis 4:15) (n)blot, smear, smirch, spot, stainan act that brings discredit to the person who does it“he made a huge blot on his copybook” Verbs
(v)staincolor with a liquid dye or tint“Stain this table a beautiful walnut color”,
“people knew how to stain glass a beautiful blue in the middle ages” (v)stainproduce or leave stains“Red wine stains the table cloth” (v)tarnish, stain, maculate, sully, defilemake dirty or spotty, as by exposure to air; also used metaphorically“The silver was tarnished by the long exposure to the air”,
“Her reputation was sullied after the affair with a married man” (v)stain, dyecolor for microscopic study“The laboratory worker dyed the specimen”