istniejcy
Istniejcy is not a standard Polish word. In Polish, the adjective meaning “existing” is istniejący, used in masculine nominative singular and forming feminine and neuter and other forms as istniejąca, istniejące, etc. The form istnejcy appears almost exclusively as a misspelling or typographical error rather than a recognized linguistic term. Because of this, istniejcy does not appear in reputable Polish dictionaries, grammars, or style guides.
Etymology and morphology: the correct formation rests on the verb istnieć (to exist) and the present participle
Orthography and error patterns: common sources of the mistake include omission of diacritics, confusion between similar
Usage and related terms: when conveying the concept of existence, Polish uses istnieć (to exist) and its