Mordant (?), a. [F., p. pr. of mordere to bite; L. mordere. See Morsel.] 1. Biting; caustic; sarcastic; keen; severe.
[1913 Webster]

2. (Dyeing & Calico Printing) Serving to fix colors.
[1913 Webster]

Mordant (?), v. t. [imp. & p. p. Mordanted; p. pr. & vb. n. Mordanting.] To subject to the action of, or imbue with, a mordant; as, to mordant goods for dyeing.
[1913 Webster]