- a tendency underlying or at variance with the obvious or superficial significance of words, actions, etc.: Even in his friendliest remarks, one could sense an undercurrent of hostility.
- a current, as of air or water, that flows below the upper currents or surface.
- a current that is not apparent at the surface or lies beneath another current
- an opinion, emotion, etc, lying beneath apparent feeling or meaning
n.1660s, “stream of water or air flowing beneath the surface or beneath another current,” a hybrid formed from under + current (n.). The figurative sense of “suppressed or underlying character” is attested from 1817.