The Collaborative International Dictionary of English v.0.48:

Unknow \Un*know"\, v. t. [1st un- + know.]
   [1913 Webster]
   1. To cease to know; to lose the knowledge of. [Obs.]
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   2. To fail of knowing; to be ignorant of. [Obs.]
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The Collaborative International Dictionary of English v.0.48:

Unknow \Un*know"\, a. [See Un- not, Know.]
   Unknown. [Obs.] "French of Paris was to her unknow."
   --Chaucer.
   [1913 Webster]