-кс

Perhaps related to Finnish -ksi (“[translative suffix]”).

-кс • (-ks)

1. translative suffix
   • V. I. Ščankina (2011) Russko-mokšansko-erzjanskij slovarʹ [Russian-Moksha-Erzya Dictionary], Saransk, →ISBN

     во-первых — васенцекс, васенцесь

     vo-pervyx — vasenceks, vasencesʹ

     first of all [in Russian] — first of all

Nominalizing suffix, e.g., касомс (kasoms, “to grow”) → касыкс (kasyks, “plant”).

-кс • (-ks)

1. nominalizing suffix