| Gender | male |
|---|---|
| Word/name | Slavic |
| Meaning | mści ("vengeance") + woj ("war, warrior") |
| Nickname(s) | Mszczuj |
| Related names | Mścisław |
Mściwój or Mściwoj is a very old Polish given name of Slavic origin, consists of two elements: mści "vengeance" and woj, derived from: wojna (war), wojownik (warrior) or wuj (uncle). A related name is: Mścisław. The Pomeranian form is Mestwin.