This is the 14728th most frequent German word.
nordwestlich
Northwest or northwesterly.
Here, 'nordwestlich' is used as an adverb, specifying the direction of travel.
Er fuhr in nordwestlicher Richtung zum Flughafen.
He drove northwest towards the airport.
In this case, 'nordwestlich' functions as an adjective to describe the specific section of the park.
Im nordwestlichen Teil des Parks gibt es einen See.
In the northwestern part of the park, there is a lake.
This usage of 'nordwestlich' is as a directional adjective to describe the relative geographic location of the city in relation to Berlin.