This is the 516th most frequent Hungarian word.
karácsonyi
"Karácsonyi" means "Christmas (related to or pertaining to Christmas)" in English.
'karácsonyi' here functions as an adjective describing 'díszekkel' (ornaments), indicating their association with the Christmas holiday.
Karácsonykor karácsonyi díszekkel szoktuk feldíszíteni a fát.
At Christmas, we usually decorate the tree with Christmas ornaments.
'karácsonyi' modifies 'hangulatot' (atmosphere), specifying the type of atmosphere characteristic to Christmas.
Szeretem a karácsonyi hangulatot.
I love the Christmas atmosphere.
'karácsonyi' acts as an adjective for 'ajándékot' (gift), categorizing it as intended for or related to Christmas.