As deep as would reach to the waist (of a standing person).(adjective)
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Use "waist-deep" in a sentence
"One o'clock came, and two o'clock, and the pirates were clustering on the highest shoal, waist-deep in water."
"And it carried understanding and command to the man at the wheel, and to Mr. Pike, waist-deep in the wash of sea below us."
"Even as I looked a bursting sea filled the runway between the house and rail, and through the doorway in which I stood the freezing water rushed waist-deep."