The Gemara, Sanhedrin 76b, states that "one who returns a lost object to a כותי (or, per the marginal notes there, גוי) is censured by the Torah. Rashi there explains: "He is thereby equating the כותי ...
Shabbos 67b says "Gad" (גד) was the name of an Amorite idol, and we shouldn't use it. Shouldn't this apply to the name "God" as well? eg. "God forbid"
The Gemara in Pesachim (ה:) says if you are holding Chometz for a gentile and Pesach comes you have to burn it. How is it possible to say that: it is Gezel Akum and even if you pay him back you ...