un·der·cur·rent /-ˌkɝənt, ˌkʌrənt/
  下麵的水流,暗流,潛流
  Un·der·cur·rent, a. Running beneath the surface; hidden. [R.] “Undercurrent woe.”
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  Un·der·cur·rent 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.   --G. Eliot.
  undercurrent
       n 1: subdued emotional quality underlying an utterance; implicit
            meaning [syn: undertone]
       2: a current below the surface of a fluid [syn: undertide]