The Collaborative International Dictionary of English v.0.48:

Milky \Milk"y\, a.
   1. Consisting of, or containing, milk.
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            Pails high foaming with a milky flood. --Pope.
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   2. Like, or somewhat like, milk; whitish and turbid; as, the
      water is milky. "Milky juice." --Arbuthnot.
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   3. Yielding milk. "Milky mothers." --Roscommon.
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   4. Mild; tame; spiritless.
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            Has friendship such a faint and milky heart? --Shak.
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   Milky Way. (Astron.) See Galaxy, 1.
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WordNet (r) 3.0 (2006):

milky
    adj 1: resembling milk in color not clear; "milky glass" [syn:
           milky, milklike, whitish]