adj. 1. a. Bitingly sarcastic: mordant satire. b. Incisive and trenchant: an inquisitor's mordant questioning. 2. Bitingly painful. 3. Serving to fix colors in dyeing. n. 1. A reagent, such as tannic acid, that fixes dyes to cells, tissues, or textiles or other materials. 2. A corrosive substance, such as an acid, used in etching. tr.v. mor·dant·ed, mor·dant·ing, mor·dants To treat with a mordant. [French, from Old French, present participle of mordre, to bite, from Vulgar Latin *mordere, from Latin mordēre; see mer- in the Appendix of Indo-European roots.] mordan·cy n. mordant·ly adv. |
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. All rights reserved.