Use up (energy) (5)
(Other definitions for spend that I've seen before include "amount" , "While away" , "Pay out or use up" , "Blue" , "Run through" .)
(Other definitions for expend that I've seen before include "Use up or disburse" , "Use up (resources)" , "Lay out, disburse" , "Use up (a resource)" , "Lavish" .)