noun. The art of excavating trenches of approach under the musketry-fire of the besieged.

noun. The undermining of a river's bank, especially if it is a cliff, by the moving water and its suspended grit.

verb. Present participle of sap.

"He did not protest beyond presently a transient frown as at a bad taste on his tongue, and a rather petulant objection to her use of analogies, which he called the sapping of language."

capping  clapping  flapping  lapping  mapping  

sap