Reconstruction:Proto-Slavic/čuxъ

Onomatopoeic, seemingly related to Proto-Slavic *čukъ (“knock, clatter”), *cukъ (“tick, tock”). Probably derived from a non-attested *čuti (“to growl, to bark”) +‎ *-xъ attested as extended *čьvati. Compare further Proto-Indo-European *kew- (“to howl, to wail”), *(s)kew- (“to shout, to scold”).

For the suffix, compare Proto-Slavic *kyxъ (“cough”), *ťuxъ (“wail”), *buxъ (“woo, cough”), *puxъ (“pant”).

*čuxъ m

1. growl, grouch, bark (low, rumbling sound)
2. puff, sniffle (action that produces rumbling noise)
3. choo (as interjection)

• *čuxati (“to choo”)

• *čьvati, *ščьvati (“to bark, to harass”)
• *xula (“reproach, unjust vilification”)
• *čula (“grumpy animal”)
• *čuxa (“sniffing animal”)
  • Russian: чу́ха (čúxa, “piglet”)

• East Slavic:
  • Russian: чух (čux), цух (cux) (interjection)
  • Ukrainian: чух (čux), шуф (šuf)
• South Slavic:
  • Bulgarian: чух (čuh), probably also кюх (kjuh), кюф (kjuf) (dialectal)
  • Slovene: čȗh (“puff, pant”)

• Georgiev, Vladimir I., editor (1986), “кюхам²”, in Български етимологичен речник [Bulgarian Etymological Dictionary] (in Bulgarian), volumes 3 (крес¹ – мѝнго¹), Sofia: Bulgarian Academy of Sciences Pubg. House, page 258: от звукоподражателна основа

From *čuti (“to sense, to feel”) +‎ *-xъ.

*čuxъ m

1. feeling, scent

   Synonyms: *usętъ, *čutьje

2. (particularly) smell, odor, stench

   Synonyms: *voňa, *ňuxъ, *smordь

• *čuxati (“to sense, to smell”)

• *čutьje (“feeling, scent”)
• *čuvьstvo (“feeling”)
• *čudlo (“sense”)

• East Slavic:
  • Ukrainian: чух (čux, “stench”)
• South Slavic:
  • Slovene: čȗh (“stench”)
• East Slavic:
  • Czech: čich
  • Polish: czuch, cuch
  • Slovak: čuch
  • Sorbian:
    • Lower Sorbian: čuch
    • Upper Sorbian: čuch

• чух in Горох.ua (Етимологія)