Reconstruction:Proto-Slavic/-nikъ

Compound masculine suffix formed by the past participle ending *-nъ +‎ *-ikъ. Forms appended to a- or ě-stems are obsolete. They are often resolved by duplicating *-nъ +‎ *-ьnъ +‎ *-ikъ: e.g. Bulgarian помазаник (pomazanik), избраник (izbranik) : Russian помазанник (pomazannik), избранник (izbrannik).

The form *-nikъ seems to be prevalent mainly in East and South Slavic. West Slavic uses instead *-nьcь (from *-nъ +‎ *-ьcь), e.g. Polish pomazaniec, wybraniec.

*-nikъ m

1. From the deverbial noun stem of imperfect verbs, forms agents or objects related to the specified verb

   From athematic or simple thematic verbs:

   *dati (“to give”) → *podanikъ (“subject”)

   *jьzbьrati (“to select, to chose out of”) → *jьzbьranikъ (“chosen one”)

   *poznati (“to get familiar with”) → *poznajьnikъ (“acquaintance”)

   From je-theme verbs:

   *učati (“to study”) → *učenikъ (“student”)

   *mǫčati (“to struggle, to try hard”) → *mǫčenikъ (“martyr”)

   *mazati (“to smear, to anoint”) → *pomazanikъ (“anointed”) (mixed ā-/je-declension)

   From ā- and jā-theme verbs:

   *tupati (“to beat, to thump”) → *tupanikъ (“beat, stroke, scuffle”) (South Slavic)

   *sъmysľаti (“to think along with”) → *sъmyšľаnikъ (“associate, collaborator”) (South Slavic)

   From ě- and ě/i-theme verbs:

   *družěti (“to be in friendly relation”) → *družаnikъ (“comrade, fellow man”) (obsolete)

   *goděti (“to get engaged”) → *goděnikъ (“fiancé”) (South Slavic)

   From ī-theme verbs:

   *negoditi (“not to get along”) → *negodьnikъ (“scammer, crook”)

   *bez (“without”) + *roditi (“to give birth”) → *bezrodьnikъ (“stateless person”)

   From v-theme verbs:

   *sluti (“to express, to utter, to call oneself”) → *slovьje (“utterance”) → *slovьnikъ (“wordlist”) (archaic ev-declension)

   *čarovati (“to charm, to amaze”) → *čarovьnikъ (“charmer”) (denominal ova-declension)

• The suffix is (normally) not used with perfective verbs, e.g. those in *-nǫti.
• The derived deverbial nouns refer to agents or concepts who have undergone the verb. For agents, who perform the verb, the suffixes *-teľь, *-ačь, *-ařь, or other similar are used. For example, compare *sъpodvižеnikъ (“associate, one who moves along with you”) (obsolete) : *dvigateľь (“engine, one who sets in motion”) ← *dvigati (“to move, to lift”).

• *-ьnikъ