obligation vs liability

obligation and liability both are nouns.

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

As nouns, liability is a hyponym of obligation; that is, liability is a word with a more specific, narrower meaning than obligation:

Other hyponyms of obligation include financial obligation, indebtedness, debt of gratitude.

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