Informant /(?)/

In·form·ant

Informant

n.
  1. One who, or that which, informs, animates, or vivifies. [Obs.]
  2. One who imparts information or instruction.
  3. One who offers an accusation; an informer. See Informer. [Obs. or R.]
    It was the last evidence of the kind; the informant was hanged.