*deepen*

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. [ 1913 Webster ]

It would . . . deepen the bed of the Tiber. Addison. [ 1913 Webster ]

2. To make darker or more intense; to darken; as, the event deepened the prevailing gloom. [ 1913 Webster ]

You must deepen your colors. Peacham. [ 1913 Webster ]

3. To make more poignant or affecting; to increase in degree; as, to deepen grief or sorrow. [ 1913 Webster ]

4. To make more grave or low in tone; as, to deepen the tones of an organ. [ 1913 Webster ]

Deepens the murmur of the falling floods. Pope. [ 1913 Webster ]