The Collaborative International Dictionary of English v.0.48:

Discoast \Dis*coast"\, v. i. [Pref. dis- + coast: cf. It.
   discostare.]
   To depart; to quit the coast (that is, the side or border) of
   anything; to be separated. [Obs.]
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         As far as heaven and earth discoasted lie. --G.
                                                  Fletcher.
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         To discoast from the plain and simple way of speech.
                                                  --Barrow.
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