the.com/confuse
To stir someone's mental waters until they can no longer see the bottom.
means To make a person unable to think clearly or understand, or to mistake one thing for another.
from From Latin confundere, literally to pour together — picture two liquids blended past separating, which is exactly what happens to your thoughts.
Sibling wordConfound shares the same pour-together Latin root.
Old senseOnce meant to defeat or ruin utterly.
Physical echoConfluence, where rivers merge, is the same root.