Undercurrent

Part of speech: noun (n.)

1. A current below the surface of water, sometimes flowing in a contrary direction to that on the surface. Totten.

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. G. Eliot.

Part of speech: adjective (a.)

Running beneath the surface; hidden. [R.] "Undercurrent woe." Tennyson.