mordant
-adjective
1. sharply caustic or sarcastic, as wit or a speaker; biting.
2. burning; corrosive.
3. having the property of fixing colors, as in dyeing.
-noun
4. a substance used in dyeing to fix the coloring matter, especially a metallic compound, as an oxide or hydroxide, that combines with the organic dye and forms an insoluble colored compound or lake in the fiber.
5. an adhesive substance for binding gold or silver leaf to a surface.
6. an acid or other corrosive substance used in etching to eat out the lines, areas, etc.
7. Music. mordent.
-verb (used with object)
8. to impregnate or treat with a mordant.
ORIGIN
1425–75; late Middle English > Middle French, present participle of mordre to bite ≪ Latin mordēre.