sustain vs establish

sustain and establish both are verbs.

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

As verbs, establish is a hyponym of sustain; that is, establish is a word with a more specific, narrower meaning than sustain:

sustain: establish or strengthen as with new evidence or facts
establish: establish the validity of something, as by an example, explanation or experiment

Other hyponyms of sustain include back, back up, vouch, verify, demonstrate, prove, shew, show, document, validate.

sustain (verb)	establish (verb)
undergo (as of injuries and illnesses)	establish the validity of something, as by an example, explanation or experiment
establish or strengthen as with new evidence or facts	institute, enact, or establish
admit as valid	use as a basis for; found on
supply with necessities and support	place
provide with nourishment	set up or lay the groundwork for
be the physical support of; carry the weight of	bring about
lengthen or extend in duration or space	build or establish something abstract
	set up or found