indebtedness vs obligation

indebtedness and obligation both are nouns.

Word	Noun	Adjective	Verb	Adverb
indebtedness	Yes	No	No	No
obligation	Yes	No	No	No

As nouns, indebtedness and obligation are synonyms defined as:

indebtedness and obligation: a personal relation in which one is indebted for a service or favor

As nouns, obligation is a hypernym of indebtedness; that is, obligation is a word with a broader meaning than indebtedness:

indebtedness (noun)	obligation (noun)
a personal relation in which one is indebted for a service or favor	the social force that binds you to the courses of action demanded by that force
an obligation to pay money to another party	a legal agreement specifying a payment or action and the penalty for failure to comply
	a written promise to repay a debt
	a personal relation in which one is indebted for a service or favor
	the state of being obligated to do or pay something