-небудзь

Belarusian

не- (nje-) +‎ будзь (budzʹ), imperative form of быць (bycʹ, “to be”), literally, “don't be”, although perhaps semantically closer to "be or not". Compare Polish bądź, Russian -нибу́дь (-nibúdʹ), Ukrainian -не́будь (-nébudʹ).

-не́будзь • (-njébudzʹ)

Always draws the stress of the word onto the first syllable of the suffix.
Certain words only have an indefinite form using -не́будзь (-njébudzʹ); for example, there exists адкуль-не́будзь (adkulʹ-njébudzʹ, “from somewhere”), but *адкульсьці (*adkulʹsʹci) is at least poorly attested. However, all -сьці (-sʹci) indefinite pronouns also have a -не́будзь (-njébudzʹ) variant: хто-не́будзь (xto-njébudzʹ), які-не́будзь (jaki-njébudzʹ), and so forth.

“-небудзь”, in Skarnik's Belarusian dictionary (in Belarusian), based on Kandrat Krapiva's Explanatory Dictionary of the Belarusian Language (1977-1984)