Is one sinful or a disbeliever if they utter the name Christmas or a foreign word in a bad way, intentionally or forgetfully, without thinking about its meaning?

It is clear from this question of yours and the previous ones that you are suffering from satanic whisperings due to your indulgence in them and surrender to them, and your lack of striving against yourself to abandon them. The optimal treatment for whisperings, after seeking Allah's help, is to turn away from them and pay them no heed. We have previously advised you to turn away from these whisperings and to focus on what benefits your religion and your worldly life. What you have asked about entails several possibilities and requires clarification, and its cause is these whisperings that have encompassed you.