Reconstruction:Proto-Slavic/čupъ

Per Snoj, from Proto-Indo-European *(s)kewp-, akin to Proto-Germanic *skuftą (“bundle, hair”). At least partially of onomatopoeic origin, equivalent to e-grade of *kujati (“to caw, to crook”) +‎ *-pъ. Similar to Proto-Slavic *čukъ (“knock”).

Probably, further related to Proto-Slavic *čubъ (“crest, forelock”) and Proto-Slavic *skuti (“to pluck (hair, weeds)”), the later akin to Lithuanian skùbti (“to hurry”), Proto-Germanic *skeubaną (“to shove”).

*čűpъ m^[1]

1. kink, crook, grapple

   → (by extension) crest (of birds), strand (of hair)

   Synonyms: *kyčurъ, *griva (partially)

2. (onomatopoeic) crack, fracture

• *čubъ (“crest, forelock”)
• *čukъ (“knock, hammer”)
• *kyka (“pigtail”)
• *kyčurъ (“tuft”)

• *čupъka (diminutive)
• *čupiti (“to crack, to break”)

• East Slavic:
  • Russian: чуп (čup) (colloquial)
• South Slavic:
  • Bulgarian: чуп! (čup!, “approx. Get out of here!”), чупка (čupka, “kink, crook; firg. bun of hair”) (diminutive)
  • Macedonian: чупа f (čupa, “crest”) (dialectal), чупе (čupe, “bonnie girl”) (diminutive)
  • Serbo-Croatian:
    • Cyrillic script: чу̏п
    • Latin script: čȕp (tuft of hair), čȕpa (hair, colloquial)
  • Slovene: čȗp (“strand of hair, tuft”) (colloquial), čȍp, čōpka (diminutive)
• West Slavic:
  • Polish: czup (colloquial)

• Vasmer, Max (1964–1973) “чуб”, in Oleg Trubachyov, transl., Этимологический словарь русского языка [Etymological Dictionary of the Russian Language] (in Russian), Moscow: Progress