To ingrain grime or dirt which is difficult to remove into (something); also (more generally), to make (something) dirty; to soil.
To dirty; to make dirty.
To harm the reputation of; to smear or slander.
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)
A stain on somebody's reputation.
Dirt, or a stain.