substance vs content

substance and content both are nouns.

Word	Noun	Adjective	Verb	Adverb
substance	Yes	No	No	No
content	Yes	Yes	Yes	No

As nouns, content is a hypernym of substance; that is, content is a word with a broader meaning than substance:

substance: the choicest or most essential or most vital part of some idea or experience
content: the sum or range of what has been perceived, discovered, or learned

Other hypernyms of substance include cognitive content, mental object.

As nouns, substance and content are synonyms defined as:

substance and content: content communicating a message; what something is about

Other synonyms of substance include message, subject matter.

substance (noun)	content (noun)
the real physical matter of which a person or thing consists	something (a person or object or scene) selected by an artist or photographer for graphic representation
a particular kind or species of matter with uniform properties	the sum or range of what has been perceived, discovered, or learned
the property of holding together and retaining its shape	content communicating a message; what something is about
the idea that is intended	(usually plural) everything that is included in a collection and that is held or included in something
the choicest or most essential or most vital part of some idea or experience	the amount that can be contained
content communicating a message; what something is about	the proportion of a substance that is contained in a mixture or alloy etc.
considerable capital (wealth or income)	the state of being contented with your situation in life
material of a particular kind or constitution

substance (adjective)	content (adjective)
	satisfied or showing satisfaction with things as they are

substance (verb)	content (verb)
	satisfy in a limited way
	make content