maintenance vs sustenance

maintenance and sustenance both are nouns.

Word	Noun	Adjective	Verb	Adverb
maintenance	Yes	No	No	No
sustenance	Yes	No	No	No

As nouns, maintenance and sustenance are synonyms defined as:

maintenance and sustenance: the act of sustaining life by food or providing a means of subsistence

Other synonyms of maintenance include sustainment, sustentation, upkeep.

As nouns, sustenance is a hypernym of maintenance; that is, sustenance is a word with a broader meaning than maintenance:

Other hypernyms of maintenance include bread and butter, keep, livelihood, living, support.

maintenance (noun)	sustenance (noun)
activity involved in maintaining something in good working order	the act of sustaining life by food or providing a means of subsistence
the act of sustaining life by food or providing a means of subsistence	a source of materials to nourish the body
the unauthorized interference in a legal action by a person having no interest in it (as by helping one party with money or otherwise to continue the action) so as to obstruct justice or promote unnecessary litigation or unsettle the peace of the community	the financial means whereby one lives
means of maintenance of a family or group
court-ordered support paid by one spouse to another after they are separated