A German.
German
Wilhelm Wundt (1832-1920) was the first person to call himself a psychologist. In 1879, he founded one of the first psychological laboratories in Leipzig, Germany.
'Hamburg' is a city in Germany. In English, one could call a person in or from Hamburg a "Hamburger" (capitalized).
We call it "weihnachten"
The Romans called Germany, "Germania".
A person who was born in Germany, or was raised in Germany but later migrated, would be a native German. This would be the person's ethnicity.
Santa is called der Weihnachtsmann in Germany.
Germany's got talent
whatchamacallit
Fußball
Deutschland
Germans