| noun | a soiled or discolored appearance “the wine left a dark stain” |
| noun | (microscopy) a dye or other coloring material that is used in microscopy to make structures visible |
| noun | the state of being covered with unclean things |
| noun | a symbol of disgrace or infamy; --Genesis “And the Lord set a mark upon Cain” |
| noun | an act that brings discredit to the person who does it “he made a huge blot on his copybook” |
| verb | color with a liquid dye or tint “Stain this table a beautiful walnut color” |
| verb | produce or leave stains “Red wine stains the table cloth” |
| verb | make dirty or spotty, as by exposure to air; also used metaphorically “The silver was tarnished by the long exposure to the air” |
| verb | color for microscopic study “The laboratory worker dyed the specimen” |
| stain | verb | produce or leave stains |
| discolor | verb | cause to lose or change color |
| discolour | verb | change color, often in an undesired manner |
| dirty | adjective | spreading pollution or contamination; especially radioactive contamination |
| filthy | adjective | disgustingly dirty; filled or smeared with offensive matter |
| grimy | adjective | thickly covered with ingrained dirt or soot |
| grime | verb | make soiled, filthy, or dirty |
| soil | verb | make soiled, filthy, or dirty |
| grease | verb | lubricate with grease |
| grungy | adjective | thickly covered with ingrained dirt or soot |
| mark | verb | to accuse or condemn or openly or formally or brand as disgraceful |
| stigmatic | adjective | pertaining to or resembling or having stigmata |
| stigmatize | verb | to accuse or condemn or openly or formally or brand as disgraceful |
| brand | verb | to accuse or condemn or openly or formally or brand as disgraceful |
| smirch | verb | charge falsely or with malicious intent; attack the good name and reputation of someone |
| stainer | noun | a worker who stains (wood or fabric) |
| stain | noun | the state of being covered with unclean things |
| tarnish | noun | discoloration of metal surface caused by oxidation |
| macula | noun | a patch of skin that is discolored but not usually elevated; caused by various diseases |
| maculation | noun | the act of spotting or staining something |
| staining | noun | (histology) the use of a dye to color specimens for microscopic study |