Finnish word syy comes from Proto-Finnic *süü (Annual ring. Blame, fault. Reason, cause. Thread, fibre.)

Detailed word origin of syy

Dictionary entry	Language	Definition
*süü	Proto-Finnic (fiu-fin-pro)	Annual ring. Blame, fault. Reason, cause. Thread, fibre.
syy	Finnish (fin)	Fault. Fibre. Filament. Grain (linear texture of a material or surface); used in plural (syyt). Reason.

Words with the same origin as syy