This is the 6703rd most frequent Polish word.
dzisiejszy
"Today's" or "of today."
In this sentence, 'dzisiejszy' is used as an adjective to describe the walk ('spacer') in relation to the current day.
Dzisiejszy spacer był bardzo relaksujący.
Today's walk was very relaxing.
Here, 'dzisiejszy' modifies 'świecie' (world) to signify contemporary times.
W dzisiejszym świecie technologia odgrywa kluczową rolę.
In today's world, technology plays a key role.
'Dzisiejsza' here functions as an adjective describing the newspaper ('gazeta') in terms of being published today.