noun

• (figuratively) A damaging or corrupting influence.
  "Women should earn equal wages with men for equal work done. Child marriages and polygamy are a gangrene on society."

verb

• (transitive) To produce gangrene in.
  "Vulneration or section sometimes procures a Gangrene, when the vital Principle is so debilitated, or enormous by the would, that instead of a good suppuration and vigorous transmutation, a depraved matter is generated, which corrupts and gangrenes the part: and thus a small cut of a finger or Toe hath gangrened, and killed the person: but in greater Wounds, the danger is greater, as more frequently to happen."
• (intransitive) To be affected with gangrene.
  "If a man had a sore leg, and he should go to an honest, judicious chirurgeon, and he should only bid him keep it warm, and anoint it with such an oil, (an oil well known) that would do the cure; haply he would not much regard him, because he knows the medicine, beforehand an ordinary medicine; but if he should go to a surgeon that should tell him, your leg will gangrene within three days, and it must be cut off, and you will die, unless you do something that I could tell you, what listening there would be to this man?"
• (transitive) To corrupt; To cause to become degenerate.
  "That is true,” replied Almira, “nothing can be performed without labor, and where there is labor there will be discontent, and where there is no labor there will be heart-burning and jealousy about insignificant trifles, such as gangrenes the real pleasures of contemplation within these walls; walls, which would otherwise hold out an asylum, much to be prized by those who have been unfortunate, who have lost all their friends, or who are weary of the world.""