NOUN (1)

1. any of various pale or light colors;


ADJECTIVE (2)

1. lacking in body or vigor;
- Example: "faded pastel charms of the naive music"

2. delicate and pale in color;
- Example: "pastel pink"

The Collaborative International Dictionary of English v.0.48:

Pastel \Pas"tel\, n. [F.; cf. It. pastello. Cf. Pastil.]
   1. A crayon made of a paste composed of a color ground with
      gum water. [Sometimes incorrectly written pastil.]
      "Charming heads in pastel." --W. Black.
      [1913 Webster]

   2. (Bot.) A plant affording a blue dye; the woad (Isatis
      tinctoria); also, the dye itself.
      [1913 Webster]

WordNet (r) 3.0 (2006):

pastel
    adj 1: lacking in body or vigor; "faded pastel charms of the
           naive music"
    2: delicate and pale in color; "pastel pink"
    n 1: any of various pale or light colors