"Fundamental" means something that is essential, basic, or necessary. It refers to the most important or foundational aspects or principles of a topic or concept. Full definition
This is an important case for the application of fundamental rights in asylum context. (europeanlawblog.eu)
This simple task brings up a whole series of fundamental questions about constitutional relationships which are, at the least, educational. (newlawjournal.co.uk)
That's a kind of fundamental principle of all of mathematics, physics, machine learning, risk assessment. (law.stackexchange.com)