Mordant (adjective)

1. Biting or caustic in manner or speech often to the point of being sarcastic.
2. Having or showing a sharp or critical quality.
3. Having a tendency to produce a biting or stinging effect.
4. Serving to fix a dye on a fabric by forming a chemical bond with it.

Origin:

Middle english, from old french, from latin mordere to bite.

Examples:

1. The comedian's mordant wit left the audience in stitches.
2. Her mordant commentary on current events was always insightful and thought-provoking.
3. The mordant humor of the film was well received by the audience.
4. The mordant solution was necessary to fix the dye on the fabric.
5. His mordant critique of the government's policies was both accurate and cutting.