tanist (n.)youdaoicibaDictYouDict[tanist 词源字典]
"elected heir of a Celtic chief," 1530s, from Gaelic tanaiste "presumptive or apparent heir to a lord," literally "parallel, second," from Old Irish tanaise "designated successor," from Celtic *tani-hessio- "one who is waited for."[tanist etymology, tanist origin, 英语词源]