From Wiktionary, the free dictionary
Late Middle High German smaz, related to schmatzen.
Schmatz m (strong, genitive Schmatzes, plural Schmatze or Schmätze)
- (informal) smacker, smackeroo, a loud kiss
- Synonym: Schmatzer
Declension of Schmatz [masculine, strong]
- “Schmatz” in Duden online
- “Schmatz” in Digitales Wörterbuch der deutschen Sprache