sapping
sap-ping
noun
The action of weakening or undermining something gradually.
"The sapping of public confidence was a serious concern."
verb
Gradually weaken or deplete (someone's energy or resources).
"The constant demands of the job were sapping her energy."
Thesaurus
Synonyms: sap, blackjack, cosh, muggins, saphead, fool, tomfool, exhaust, tire, play out, run down