The Collaborative International Dictionary of English v.0.48:

Mellow \Mel"low\, a. [Compar. Mellower; superl. Mellowest.]
   [OE. melwe; cf. AS. mearu soft, D. murw, Prov. G. mollig
   soft, D. malsch, and E. meal flour.]
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   1. Soft or tender by reason of ripeness; having a tender
      pulp; as, a mellow apple.
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   2. Hence:
      (a) Easily worked or penetrated; not hard or rigid; as, a
          mellow soil. "Mellow glebe." --Drayton
      (b) Not coarse, rough, or harsh; subdued; soft; rich;
          delicate; -- said of sound, color, flavor, style, etc.
          "The mellow horn." --Wordsworth. "The mellow-tasted
          Burgundy." --Thomson.
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                The tender flush whose mellow stain imbues
                Heaven with all freaks of light.  --Percival.
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   3. Well matured; softened by years; genial; jovial.
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            May health return to mellow age.      --Wordsworth.
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            As merry and mellow an old bachelor as ever followed
            a hound.                              --W. Irving.
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   4. Warmed by liquor; slightly intoxicated. --Addison.
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