\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.

\Deep"en\, v. i.
To become deeper; as, the water deepens at every cast of the
lead; the plot deepens.
      His blood-red tresses deepening in the sun. --Byron.