mordant
1. mor.dant \'mo.rd-*nt\ aj [MF, prp. of mordre to bite, fr. L morde-re] 1: biting and caustic in thought, manner, or style : INCISIVE 2: acting as a mordant 3: BURNING, PUNGENT - mor.dant.ly av 2. mordant n 1: a chemical that fixes a dye in or on a substance by combining with the d ye to form an insoluble compound 2: a corroding substance used in etching 3. mordant vt : to treat with a mordant