- DEEPEN
- Intensify
- Make more intense
- Become more profound
- Become more intense
- Get less superficial
- Get farther down
- Increase the volume of, in a way
- Excavate further
- Change the channel?
- Grow more intense
- Become more complex
- Dig farther down
- Go lower
- Grow in intensity
- Make more navigable, as a channel
- Dredge, say
- Become more heartfelt
- Get more profound
- Become more complicated
- Extend farther down
- Get lower
- Keep digging
- Expand
- Dredge, perhaps
- Grow more profound
- Compound
- Get more complicated
- Complicate
- Dig further down
- Get complicated
- Dig down?
- Keep dredging
- Extend downward.
- Render darker.
- Dredge.
- Become intense.
- Increase in degree.
- Grow more obscure.
- Make more profound.
- Dig further
- Make darker
- Become more serious
- Excavate
- Get worse, as losses
- Grow, as sympathies
- Get more complex, as a mystery
- Become richer and more nuanced, perhaps
- Compound or intensify
- Make more meaningful
- Thicken, as a mystery
- Continue dredging
- Gain intensity
- Grow stronger, as a friendship
- Get more intense
- Dig out
- Dredge, maybe
- Make navigable, maybe
