This is the 17948th most frequent Polish word.
świąteczny
"Świąteczny" means "festive" or "holiday-related."
The word "świątecznych" here functions as an adjective, describing "kolacji" (dinners), and implies that the dinners are related to a holiday or festive occasion.
Polska tradycja świątecznych kolacji jest bardzo bogata.
The Polish tradition of holiday dinners is very rich.
The word "świąteczny" here acts as an adjective describing "nastrój" (mood), indicating that the mood has the qualities or atmosphere associated with holidays.
Świąteczny nastrój wypełnił całą rodzinę.
The holiday mood filled the entire family.
The word "świąteczne" functions as an adjective modifying "dekoracje" (decorations), showing that the decorations are related to or thematic of a holiday season.