Definition of smirching:
(n) :
(figurative, archaic) A stain on somebody's reputation.
(v) :
(transitive, figurative, archaic) To harm the reputation of; to smear or slander.
(v) :
(transitive, archaic) To dirty; to make dirty.
(n) :
(archaic) Dirt, or a stain.
(n) :
(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)