We don't have synonyms for viaticum yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are viaticus, viatic and viatical.
(n) :
the Eucharist, when given to a person who is dying or one in danger of death; provisions, money, or other supplies given to someone setting off on a long journey (often figurative)
"1885: Towards night-fall he entered a town called Sa'adiyah where he alighted and took out somewhat of his viaticum and ate -- Sir Richard Burton, The Book of the Thousand Nights and a Night (Night 20)"
(n) :
the Eucharist, when given to a person who is dying or one in danger of death; provisions, money, or other supplies given to someone setting off on a long journey (often figurative)
"1885: Towards night-fall he entered a town called Sa'adiyah where he alighted and took out somewhat of his viaticum and ate -- Sir Richard Burton, The Book of the Thousand Nights and a Night (Night 20)"