commitment vs subject matter

commitment and subject matter both are nouns.

Word	Noun	Adjective	Verb	Adverb
commitment	Yes	No	No	No
subject matter	Yes	No	No	No

As nouns, subject matter is a hypernym of commitment; that is, subject matter is a word with a broader meaning than commitment:

Other hypernyms of commitment include content, message, substance.

commitment (noun)	subject matter (noun)
the act of binding yourself (intellectually or emotionally) to a course of action	content communicating a message; what something is about
the official act of consigning a person to confinement (as in a prison or mental hospital)
an engagement by contract involving financial obligation
the trait of sincere and steadfast fixity of purpose
a message that makes a pledge