IPA: /ˈrʌtiər/
KK: /ˈrʌtɪər/
A chart that shows a planned route, especially for navigation at sea.
The captain studied the ruttier to ensure a safe passage through the waters.
The word 'ruttier' is derived from 'rut' (from Old English 'rūte', meaning a track or path) and the suffix '-ier' (meaning one who or that which). Thus, 'ruttier' refers to something that is more like a rut or has more ruts than something else.
Think of a 'rut' as a track or path, and remember that 'ruttier' means having more of those tracks or paths.