eavesdropper

Have you ever wondered about what life is like for a professional U.S. government eavesdropper?

But the eavesdropper heard with full appreciation the richness of the low voice and could not wonder at Bob's delight in it.

At this juncture the couple turned their backs upon the eavesdropper, who had stolen to within a few paces of them.

I was an eavesdropper entirely by accident, but what I heard might help some.

Let him play eavesdropper if he finds it consistent with his character as a gentleman.

That he had unwittingly played eavesdropper troubled him not a little.