Undercurrent /(?)/

Un·der·cur·rent

Undercurrent

n.
  1. A current below the surface of water, sometimes flowing in a contrary direction to that on the surface.
  2. Hence, figuratively, a tendency of feeling, opinion, or the like, in a direction contrary to what is publicly shown; an unseen influence or tendency; as, a strong undercurrent of sentiment in favor of a prisoner.
    All the while there was a busy undercurrent in her.

Undercurrent

a.
  1. Running beneath the surface; hidden. [R.]