A Noldorin word for “northern” in The Etymologies of the 1930s that is either forvein or fervein, an adjectival form of N. forven “north” and the cognate of ᴹQ. formenya (Ety/PHOR; EtyAC/PHOR).
Neo-Sindarin: This word might be adapted into Neo-Sindarin as forvain or fervain, but I would just use N. forodren for “northern” instead.
An adjectival form of forod “north” in The Etymologies of the 1930s (Ety/PHOR).