Depends on how it's used
Before you criticize someone you should walk a mile in their shoes, that way when you do criticize them you'll be a mile away and you'll have their shoes.
The word Jew itself isn't offensive.
However, one can use it in such a way as to insult by implying it as some kind of negative.
"Look at you skimping on the check, you're such a jew".
"Man, why'd you have to go and be a Jew, you could've afforded those concert tickets"
In those cases, the person is attemtping to use "Jew" as an insult by suggesting negative stereotypes that are commonly assigned to the people the term references. That doesn't make the term "jew" in and of itself offensive, but rather the way the person is using it.
"I am appalled that somebody who is the nominee...would take that kind of position"
"A court took away a presidency"
"...the brother of a man running for president was the governor of the state..."
It's horrifying because Trump is blunt instead of making overt implications.
Man, you got jew'd by that salesman.
What's wrong with you, why you jewing me?
I HAD that HS, wtf so jew.
Examples of offensive use of the word JEW.
⚧ C.T.L.W. You figure it out
My Endo doc went over my blood work. "I see your estrogen level is now at 315, do you feel like you have too much Estrogen now?"
I told her "... N... N.. No..." and started crying.
No it isn't, but depending on the context in which a person uses the word it can be seen as offensive. Like when some people call me a Yank to show their hatred for the North.
It's not typically offensive, however this man makes it so.
Tired of elections being between the lesser of two evils.When the debate is lost, slander becomes the tool of the loser. -Socrates
As always, depends on context. We had a poster here that called me "Jew" with absolute intent to be offensive. Other times I've been called "a Jew" with no offense intended. If you think about it though, calling someone "a Jew" sounds aggressive. Usually better to call someone Jewish.
"Never fear. Him is here" - Captain Chaos (Dom DeLuise), Cannonball Run
Mace Windu: Then our worst fears have been realized. We must move quickly if the Jedi Order is to survive.