Północny zachód and other 84,100 icons from Icons8 icon pack follow the visual guidelines of the operating systems: Windows, iOS, Android KitKat, and Material. PNG format is free up to 100x100 px. Icons are availble for download in PNG and vector (SVG, PDF, EPS, and more).
It's a sign to point to the direction known as North West. The outer arrow shape is pointing diagonally to the upper left, similar to the position of 10 on a clock. There are the letters NW inside the arrow shape.