enervate
verb
make (someone) feel drained of energy or vitality.
the heat enervated us all
exhaust,tire,fatigue,weary,wear out,devitalize,drain,sap,weaken,make weak,make feeble,enfeeble,debilitate,incapacitate,indispose,prostrate,immobilize,lay low,put out of action,knock out,do in,take it out of one,shatter,poop,frazzle,wear to a frazzle,fag out,knacker,torpefy
adjective
lacking in energy or vitality.
the enervate slightness of his frail form