'Informant' definitions:

Definition of 'informant'

From: WordNet
noun
A person who supplies information [syn: informant, source]
noun
Someone who sees an event and reports what happened [syn: witness, witnesser, informant]

Definition of 'Informant'

From: GCIDE
  • Informant \In*form"ant\, n. [L. informans, -antis, p. pr. of informare. See Inform, v. t.]
  • 1. One who, or that which, informs, animates, or vivifies. [Obs.] --Glanvill. [1913 Webster]
  • 2. One who imparts information or instruction. [1913 Webster]
  • 3. One who offers an accusation; an informer. See Informer. [Obs. or R.] [1913 Webster]
  • It was the last evidence of the kind; the informant was hanged. --Burke. [1913 Webster]