- sunk to the knees: standing knee-deep in water
- so deep as to reach to the knees: knee-deep mud
- very much involved or concerned
See knee-deep in American Heritage Dictionary 4
- Reaching as high as the knees: knee-deep floodwaters.
- Submerged to the knees: was knee-deep in mud.
- Deeply occupied or involved: is knee-deep in work.
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