Reconstruction:Proto-Slavic/-unъ

• *-ynъ

Probably irregularly from the poorly attested earlier form *-ynъ (compare *-urъ / *-yrъ), from Proto-Balto-Slavic *-ūnas.

If not, compare Ancient Greek -αυνός (-aunós) attested in κεραυνός (keraunós, “thunderbolt”) and possible derivative ἐλαύνω (elaúnō) (< *ἐλαυνός (*elaunós)).

*-ũnъ m^[1][2]

1. Forms names of persons or things that do an action indicated by the root verb: -er

   ‎*běťi / *běgati (“to run”) + ‎*-unъ → ‎*běgunъ (“runner”)

   ‎*opeťi (“to take care, to look after”) + ‎*-unъ → ‎*opekunъ (“carer, caregiver”)

   ‎*zьdati (“to form out of clay”) + ‎*-unъ → ‎*zьdunъ (“clayster, potter”)

• East Slavic:
  • Old East Slavic: -унъ (-unŭ)
    • Old Ruthenian: -унъ (-un)
      • Belarusian: -ун (-un)
      • Carpathian Rusyn: -ун (-un)
      • Ukrainian: -ун (-un)
    • Russian: -ун (-un)
• South Slavic:
  • Old Church Slavonic:

    Old Cyrillic script: -оунъ (-unŭ)

    • Bulgarian: -ун (-un)
    • Macedonian: -ун (-un)
  • Serbo-Croatian:

    Cyrillic script: -ун

    Latin script: -un

  • Slovene: -un (tonal orthography)
• West Slavic:
  • Old Czech: -ún
    • Czech: -oun
  • Old Polish: -un
    • Polish: -un
    • Silesian: -ōn
  • Old Slovak: -ún
    • Slovak: -ún
  • Pomeranian:
    • Kashubian: -ùn
  • Sorbian:
    • Lower Sorbian: -un
    • Upper Sorbian: -un