sustentativeyoudaoicibaDictYouDict[sustentative 词源字典]
"Having the quality or purpose of sustaining something; providing sustenance or support; relating to sustentation", Early 17th cent.; earliest use found in Thomas Jackson. From post-classical Latin sustentativus from classical Latin sustentāt-, past participial stem of sustentāre + -īvus.[sustentative etymology, sustentative origin, 英语词源]