adj serving to fix colors.
2. mordant ·noun any corroding substance used in etching.
3. mordant ·adj biting; caustic; sarcastic; keen; severe.
4. mordant ·noun any sticky matter by which the gold leaf is made to adhere.
5. mordant ·vt to subject to the action of, or imbue with, a mordant; as, to mordant goods for dyeing.
6. mordant ·noun any substance, as alum or copperas, which, having a twofold attraction for organic fibers and coloring matter, serves as a bond of union, and thus gives fixity to, or bites in, the dyes.