This is the 4947th most frequent Russian word.
конституционных
"Constitutional."
Here, 'конституционных' describes 'the rights' as being derived from or related to the constitution.
Конституционных прав граждан нельзя нарушать.
The constitutional rights of citizens cannot be violated.
In this instance, 'конституционных' modifies 'reforms', indicating that the reforms pertain to the constitution.
Вопросы конституционных реформ обсуждались на заседании.
The issues of constitutional reforms were discussed at the meeting.
Here, 'конституционных' is an adjective describing 'laws', specifying their association with the constitution.