The Collaborative International Dictionary of English v.0.48:

Hush \Hush\ (h[u^]sh), v. t. [imp. & p. p. Hushed (h[u^]sht);
   p. pr. & vb. n. Hushing.] [OE. huschen, hussen, prob. of
   imitative origin; cf. LG. hussen to lull to sleep, G. husch
   quick, make haste, be silent.]
   1. To still; to silence; to calm; to make quiet; to repress
      the noise or clamor of.
      [1913 Webster]

            My tongue shall hush again this storm of war.
                                                  --Shak.
      [1913 Webster]

   2. To appease; to allay; to calm; to soothe.
      [1913 Webster]

            With thou, then,
            Hush my cares?                        --Otway.
      [1913 Webster]

            And hush'd my deepest grief of all.   --Tennyson.
      [1913 Webster]

   To hush up, to procure silence concerning; to suppress; to
      keep secret. "This matter is hushed up." --Pope.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

hushed \hushed\ (h[u^]sht), adj.
   1. having the sound level reduced; -- especially used of the
      noise of conversation; as, speaking in hushed tones.

   Syn: muted.
        [WordNet 1.5]

   2. having relatively little noise; as, a hushed church.

   Syn: quiet.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

hushed
    adj 1: in a softened tone; "hushed voices"; "muted trumpets"; "a
           subdued whisper"; "a quiet reprimand" [syn: hushed,
           muted, subdued, quiet]