Q: Is it permissible to wish others “Merry Christmas” or “Happy New Year”?
A: Your query refers. It is not permissible to wish non-Muslims Merry Christmas, because such a greeting is a religious greeting and we Muslims are not allowed to adopt any custom or style of their religion. The hadith also prohibits greeting in a non-Muslim way.
Saying ‘happy new year’ is makrooh, not totally haraam because this is not a religious term. But it is better to avoid even this. In place of both types of greetings, we can merely say to them: “we wish you well over the festive season” or “greetings for the festive season” and when saying this have this intention in the heart that you are making dua of guidance for them. Wishing them well is actually wishing that Allah guide them to Islam
And Allah Ta’ala knows best
Mufti Siraj Desai