This is the 12454th most frequent Polish word.
nadmorskich
"Coastal."
In this sentence, 'nadmorskich' is an adjective describing 'restauracjach' (restaurants), specifying their location in a coastal area.
Smakowałem potrawy w nadmorskich restauracjach.
I tasted dishes in the coastal restaurants.
The word 'nadmorskich' is used as an adjective describing 'krajobrazów' (landscapes), indicating their coastal nature.
Podziwiałem piękno nadmorskich krajobrazów.
I admired the beauty of coastal landscapes.
Here, 'nadmorskich' modifies 'parku' (park), linking the location to the coastal area.