verb

make (a noise or sensation) less strong or intense.

ether was used to deaden the pain

numb,stifle,dull,blunt,suppress,alleviate,mitigate,moderate,weaken,diminish,reduce,decrease,lessen,palliate,abate,ease,soothe,relieve,assuage,subdue,take the edge off,get rid of,put an end to,muffle,mute,smother,damp,damp down,tone down,hush,silence,quieten,soften,cushion,blanket,buffer,absorb,quiet