Saying "mazel tov" at a Christmas party is a bit unusual and might raise some eyebrows, as "mazel tov" is a Hebrew and Yiddish expression typically used to offer congratulations or good wishes on special occasions, particularly in Jewish culture. The phrase is commonly used to celebrate events such as weddings, bar mitzvahs, and other joyous occasions in the Jewish community.
Using "mazel tov" at a Christmas party could be a misunderstanding or a slip of the tongue. It's possible that the person saying it is not aware of its cultural significance or is trying to be humorous or playful by using a phrase from a different cultural context. However, it's essential to be sensitive to cultural norms and customs, especially when using expressions from other traditions.
To avoid any confusion or potential offense, it's best to stick to more appropriate holiday greetings and expressions related to Christmas when at a Christmas party. Common greetings for Christmas include "Merry Christmas," "Happy Holidays," "Season's Greetings," or "Happy Christmas," depending on the cultural context. These greetings are more aligned with the spirit of the celebration and are widely accepted in the context of Christmas festivities.