This is the 1605th most frequent German word.
rechtliche
"Rechtliche" means "legal" or "relating to law."
In this sentence, 'rechtliche' is used as an adjective to describe 'Grundlagen' (foundations), indicating they pertain to law or legality.
Die rechtlichen Grundlagen für diese Regelung sind eindeutig geregelt.
The legal foundations for this regulation are clearly defined.
Here, 'rechtliche' modifies 'Probleme' (problems), indicating these issues are related to legal matters.
Sie hatten rechtliche Probleme mit der Vertragserfüllung.
They had legal problems with fulfilling the contract.
In this context, 'rechtliche' is an adjective describing 'Verfahren' (procedure), specifying that it is of a legal nature.