This is the 205th most frequent Dutch word.
mooie
"Beautiful" or "pretty."
Here, 'mooie' is used as an adjective to describe 'bloem' (flower), indicating its quality (beautiful). It agrees in gender, number, and definiteness with the noun.
Dat is een mooie bloem.
That is a beautiful flower.
In this case, 'mooie' is used to describe 'jurk' (dress), showing the aesthetic quality of the noun being described.
Ze droeg een mooie jurk naar het feest.
She wore a beautiful dress to the party.
Here, 'mooie' qualifies 'stad' (city), emphasizing its pleasant appearance or qualities. 'Mooie' changes form due to the definite article and the consonance of noun properties (e.g., preceding 'stad' in Dutch).