fundamental law vs constitution

fundamental law and constitution both are nouns.

Word	Noun	Adjective	Verb	Adverb
fundamental law	Yes	No	No	No
constitution	Yes	No	No	No

As nouns, fundamental law and constitution are synonyms defined as:

fundamental law and constitution: law determining the fundamental political principles of a government

Other synonyms of fundamental law include organic law.

fundamental law (noun)	constitution (noun)
law determining the fundamental political principles of a government	the act of forming or establishing something
	the way in which someone or something is composed
	law determining the fundamental political principles of a government