This is the 4317th most frequent Polish word.
europejskiego
"Europejskiego" means "European" (genitive singular form).
In this sentence, "europejskiego" describes "rynku" (market), serving as an adjective to indicate association with Europe.
Unia Europejska jest jednym z najważniejszych podmiotów europejskiego rynku.
The European Union is one of the most important entities of the European market.
Here, "europejskiego" modifies "transportu" (transport) to specify that the transport pertains to Europe.
Rozwój europejskiego transportu jest kluczowy dla współpracy międzynarodowej.
The development of European transport is crucial for international collaboration.
In this context, "europejskiego" qualifies "prawa" (law) to denote its origin or association with Europe.