Source : Webster's Revised Unabridged Dictionary (1913)

Deepen \Deep"en\, v. t. [imp. & p. p. {Deepened}; p. pr. & vb.
   n. {Deepening}.]
   1. To make deep or deeper; to increase the depth of; to sink
      lower; as, to deepen a well or a channel.

            It would . . . deepen the bed of the Tiber.
                                                  --Addison.

   2. To make darker or more intense; to darken; as, the event
      deepened the prevailing gloom.

            You must deepen your colors.          --Peacham.

   3. To make more poignant or affecting; to increase in degree;
      as, to deepen grief or sorrow.

   4. To make more grave or low in tone; as, to deepen the tones
      of an organ.

            Deepens the murmur of the falling floods. --Pope.

Source : WordNet®

deepened
     adj : having accumulated or become more intense; "the deepened
           gloom" [syn: {gathered}]