wear away the earth beneath, removing support
weaken or destroy gradually
"The Resistance sabotaged railroad operations during the war"
"The river was caving the banks"
We must under-mine the gate..; we must pull up the pavement until we can creep under.
出自: F. Marryat
Necessarie it is..to undermine a great way by candle-light..under the mountains.
出自: absol.