We don't have synonyms for relict yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are relic, relics and reluct.
(n) :
the surviving member of a married couple after one or the other has died; a widow or widower; a species or other structure which has survived from a previous age
(n) :
the surviving member of a married couple after one or the other has died; a widow or widower; a species or other structure which has survived from a previous age