Definitions

1. adjective

being or extending too far below the surrounding level

“The overdeep ravine was formed by millions of years of erosion.”

2. noun

a place that is overdeep, especially a ravine or valley

“The team of geologists studied the unique characteristics of the overdeep.”

3. verb

to excavate or erode too far below the surrounding level

“The river overdeepened the valley over time.”