The Collaborative International Dictionary of English v.0.48:

Sleepy \Sleep"y\, a. [Compar. Sleepier; superl. Sleepiest.]
   [AS. sl?pig. See Sleep, n.]
   1. Drowsy; inclined to, or overcome by, sleep. --Shak.
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            She waked her sleepy crew.            --Dryden.
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   2. Tending to induce sleep; soporiferous; somniferous; as, a
      sleepy drink or potion. --Chaucer.
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   3. Dull; lazy; heavy; sluggish. --Shak.
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            'Tis not sleepy business;
            But must be looked to speedily and strongly. --Shak.
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   4. Characterized by an absence of watchfulness; as, sleepy
      security.
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   Sleepy duck (Zool.), the ruddy duck.
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