Similar words: water under the bridge, underwater, watershed, waterspout, groundwater, understate, understatement, underestimate.
1. Still waters run deep.
2. Shallow streams still waters run deep.
3. Shallow streams make most din; still waters run deep.
4. Oh, no. He's quite clever. Do you know still waters run deep?
5. Till now I couldn't understand his wisdom and his honesty still waters run deep.
More similar words: water under the bridge, underwater, watershed, waterspout, groundwater, understate, understatement, underestimate, still, instill, distill, bastille, hallway, watergate, stillness, standstill, cell wall, distillation, water, undersea, watery, titillate, undersell, understand, titillated, by water, waterway, underscore, understudy, scintillate.