A person who advocates the primacy of the named entity (who puts it first)(noun)
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Use "firster" in a sentence
"Shorter Arnold Evans: The definition of an Israel firster is someone who doesn’t think that the Government of Israel should go out of business."
"Whether or not you agree with Lieberman or even like him as a person, I'm thoroughly sick of seeing accusations in this comment area accusing him of being an "Israel-firster" or a traitor to this country."
"Why would Congress entrust Israel-firster Jew Lieberman with this task?"