This is the 7668th most frequent German word.
günzburg
"Günzburg" is a proper noun referring to a town in Bavaria, Germany.
In this sentence, 'Günzburg' is used as a proper noun, specifically the name of a city in Germany.
Ich besuchte Günzburg letzten Sommer, und die Stadt war wunderschön.
I visited Günzburg last summer, and the city was beautiful.
Here, 'Günzburger' is an adjective derived from the city name 'Günzburg', used to describe something pertaining to Günzburg.
Das Günzburger Münster ist ein berühmtes Wahrzeichen.
The Günzburg Cathedral is a famous landmark.
In this context, 'Günzburger' is used as part of the proper adjective phrase to describe the surrounding area of Günzburg.