support vs sustain

support is a noun but sustain is not a noun.

Word	Noun	Adjective	Verb	Adverb
support	Yes	No	Yes	No
sustain	No	No	Yes	No

As verbs, support and sustain are synonyms defined as:

support and sustain: establish or strengthen as with new evidence or facts

Other synonyms of support include affirm, confirm, corroborate, substantiate.

As verbs, support and sustain are synonyms defined as:

Other synonyms of support include hold, hold up.

support (noun)	sustain (noun)
aiding the cause or policy or interests of
the act of bearing the weight of or strengthening
documentary validation
a military operation (often involving new supplies of men and materiel) to strengthen a military force or aid in the performance of its mission
the activity of providing for or maintaining by supplying with money or necessities
any device that bears the weight of another thing
supporting structure that holds up or provides a foundation
something providing immaterial assistance to a person or cause or interest
a musical part (vocal or instrumental) that supports or provides background for other musical parts
the financial means whereby one lives
financial resources provided to make some project possible

support (verb)	sustain (verb)
establish or strengthen as with new evidence or facts	undergo (as of injuries and illnesses)
put up with something or somebody unpleasant	establish or strengthen as with new evidence or facts
adopt as a belief	admit as valid
argue or speak in defense of	supply with necessities and support
be a regular customer or client of	provide with nourishment
be the physical support of; carry the weight of	be the physical support of; carry the weight of
play a subordinate role to (another performer)	lengthen or extend in duration or space
support materially or financially
give moral or psychological support, aid, or courage to
be behind; approve of
support with evidence or authority or make more certain or confirm