A friend of mine told me that the word "scrabble" is a forbidden name in China.

I guess this would because the word "scrabble" is related to something about sex in English slang.

Scrabble SEX of any sort.

The term "Scrabble" is a euphenism used when someone (parents, young children,your girlfriend/wife, the police) else may be listening to the conversation.

To play scrabble, is to perform sexual intercourse or a sexual act.