This is the 4538th most frequent German word.
prächtig
Splendid; magnificent; grand.
Here, 'prächtig' is used as an adjective to describe the castle, emphasizing its grand and impressive nature.
Das prächtige Schloss wurde im 18. Jahrhundert erbaut.
The magnificent castle was built in the 18th century.
In this sentence, 'prächtig' is used adverbially after the verb 'blühen' to express the blossoming of the flowers in an outstanding manner.
Die Blumen im Garten blühen prächtig.
The flowers in the garden are blooming splendidly.
'Prächtig' is used here as part of an exclamation, modifying 'Tag' to indicate that the day is particularly delightful or excellent.