dumviva

A preposition used as a prefix. Dum at rank 68 is during. Bolt it onto vivo and add -a and you have during-life, lifelong. Esperanto does this with prepositions constantly and it is one of the quiet reasons the vocabulary feels small: superbazaro at 2,592 is super plus bazaro, a supermarket; antaŭtago is the day before; postmorta is posthumous; subakva is underwater; ĉirkaŭvojo is a detour. Once the pattern is visible you stop learning these as separate words and start reading them.

Where it turns up. Almost always in the vocabulary of institutions. Dumviva membro is a life member, which in the Esperanto movement is a real category with a real fee. Dumviva prezidanto is president for life, which history suggests is rarely a good sign. Dumviva puno is a life sentence, and dumviva lernado is lifelong learning, which is the phrase every education ministry in Europe has been using since about 1996.

The near neighbours. Eterna at 617 is eternal and means without end at all; dumviva has a very definite end, and says so. Konstanta at 1,392 is constant, which is about steadiness rather than length. The adverb dumvive is common: li restis dumvive fidela al la lingvo.