Home › Words › U › underreserveunderreserveunderreserve means to put an inadequate amount of money in reserve.Among words judged in Lexicurio's Arena, underreserve ranks #16,781 of 42,791 for Qualifying.EtymologyFrom under- + reserve.verbTo put an inadequate amount of money in reserve.Definitions & examples from Wiktionary (CC BY-SA 3.0).