We don't have synonyms for hallantide yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are hollantide, hallowtide and ballantine.
(n) :
(obsolete, dialectal, West Country, Ireland, Isle of Man, Lincolnshire, Northampton, Worcestershire, Shropshire, Gloucestershire, Hertfordshire, Isle of Wight, Wiltshire, Somerset, Cornwall) All Saints' Day
(n) :
(obsolete, dialectal, West Country, Ireland, Isle of Man, Lincolnshire, Northampton, Worcestershire, Shropshire, Gloucestershire, Hertfordshire, Isle of Wight, Wiltshire, Somerset, Cornwall) All Saints' Day