"to pay out or away" (money or wealth), Old English -spendan (in forspendan "use up"), from Medieval Latin spendere, a shortening of Latin expendere "to weigh out money, pay down" (see expend) or possibly of dispendere "to pay out." A general Germanic borrowing (Old High German spendon, German and Middle Dutch spenden, Old Norse spenna). In reference to labor, thoughts, time, etc., attested from c. 1300. Intransitive sense "exhaust, wear (oneself) out" is from 1590s (see spent).
<a href="https://www.etymonline.com/word/spending">Etymology of spending by etymonline</a>
Harper, D. (n.d.). Etymology of spending. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/spending