Anti-Zionists have a funny relationship with the meaning of words. This leads to a strange relationship between them and dictionaries. Sometimes the dictionary is their best friend, and then it is not, and then it is again. If the dictionary were in a relationship with anti-Zionists, I would suggest that the dictionary end it immediately.
Here are a few examples, drawing on what Matt has already covered here.
I guess we'll start with the most obvious: Talking about anti-Semitism. When discussing that issue anti-Zionists will begin by using the dictionary to look up not "anti-Semitism" but "Semite." They therefore conclude that because "Semite" means people of Semitic dissent "anti-Semitism" does not mean hatred of Jews. The dictionary disagrees, of course, but it is forgotten now that it has served it's purpose in a tool against anti-Semitism.
Then there are systems of government: According to the dictionary, Israel is neither an "apartheid" nor a "theocracy," but that won't stop the AZs from calling it that anyway. And in fact some have been prone to make statements along the lines of: "You can quote the dictionary all you like I'm still right!" But then when they want to accuse Israel of a "massacre" or "genocide" they go right back to the dictionary as an unshakable and objective source, even if it means contorting the definition of those words beyond all recognition.
I feel bad for the dictionary, to be picked up, used and then discarded like that. Like I have said before, I don't mind people having different points of view than I do, but I don't like hypocrisy. Either the dictionary and certain other sources (like "international law") are legitimate and right or they are not.