What is the actual definition of xenophobia? Is it misused nowadays?

My theory is that xenophobia entered English through the EU's widespread use of "xenophobia" as the official translation for the German word Ausländerfeindlichkeit, which literally translates as "antipathy to foreigners" but I would normally call "anti-immigrant sentiment". I'm a German-to-English translator and so am biased in this respect, but I started learning about xenophobia about 20 years ago when I was training to be a conference interpreter and one of my professors dredged up a lot of EU speeches on Ausländerfeindlichkeit and insisted on us calling it "xenophobia".

Of course, this is just my personal experience.

Actually Xenos meant a Greek speaking foreigner to Greece, e.g. a Roman who spoke Greek (like Julius Caesar).

A barabaros is the Greek word to denote a foreigner who could not speak any Greek (and Romans felt same if one could not speak either Greek or Latin). Thus exists the word barbarian.

So strictly speaking Xenophobia should only apply to the Schismatic Greeks. Truth is they fear the Latin Filioque and Roman customs, thus they fear the Union of Florence, and rejected it. That is the real Xenophobia because many of the Latin scholars and bishops could speak Greek at the time and this persists to this day. This is only literary meaning which this word can apply to in fact.

Based on the Trojan War Romans celebrate through Virgil the adage to fear the gifts of the Greek: "I fear the Danaans [Greeks], even those bearing gifts" as said by the Trojan priest Laocoön as he warned of accepting the Greek's gift of a great wooden horse to appease Poseidon. The rest is history. To fear something for a good reason as Laocoön did makes sense for the reason of good commonweal and prophetic wisdom foreseeing danger - that is the nature of the fear - a horse would come to bring utter chaos and destruction. Of course fearing the equestrian gift is NOT a xenophobia. It is a caution, prudence, and vigilance. Unfortunately for the Trojans they did not see the reason for his fear by means of their ignorance and thereby accepted it.

So let the Xenophobia invoked by Barbarians cease - they have no right to claim its usage - and by common logic of mind this both Greek and Roman can agree to -that ancient letters and honor of their Fathers should remain in tact and not stained by Barbarians who pretend to be educated in Classics (or not even!) and misuse the words of the eloquent tongue to pronounce a misnomer. Let it cease! Invent your own barble (new word coined as Barbarian babble).