(archaic) Dirt, or a stain.

(figurative, archaic) A stain on somebody's reputation.

(astronomy) A chirp of radiation power from an astronomical body that has a smeared appearance on its plot in the time-frequency plane (usually associated with massive bodies orbiting supermassive black holes)

(transitive, archaic) To dirty; to make dirty.

(transitive, figurative, archaic) To harm the reputation of; to smear or slander.