"Icing" is also an infraction in the game of ice hockey.

It's the sweet topping on a cake or brownies, etc

Note that you cannot ask a question by saying 'What means...?'. Your question should be this: "What does icing mean?' The word order for questions is as follows: Question word = What Auxiliary = does Subject = 'icing' Main verb = mean? If you ice a cake, you put a sweet sugary layer on top of it. This topping is called icing. I can't think of a situation where 'icing' would mean a plastic object.

A synonym would be "frosting."