pierwszorzdnych
Pierwszorzdnych is not a standard entry in contemporary Polish dictionaries. It appears to be a nonstandard form, most likely a misspelling or OCR/readability variant of pierwszorędnych, the genitive plural of pierwszorędny. The latter adjective is used to mean “first-rate” or “of the first order,” i.e., top-tier or principal in quality, importance, or rank. Because classic Polish adjectives inflect for gender, number, and case, the exact spelling and form of such terms can vary in non-authoritative texts, leading to forms like pierwszorzdnych in mistaken contexts.
Etymology and meaning: pierwszorędny presumably combines pierwszy (first) with a suffix deriving from rząd, rank or
Usage: In proper Polish, one would expect forms derived from pierwszorędny rather than the unrecognized pierwszorzdnych.
See also: pierwszorędny, drugorzędny, pierwszorządność (contextual variants for related concepts).