carry on vs sustain

carry on and sustain both are verbs.

Word	Noun	Adjective	Verb	Adverb
carry on	No	No	Yes	No
sustain	No	No	Yes	No

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

carry on (verb)	sustain (verb)
continue talking	undergo (as of injuries and illnesses)
direct the course of; manage or control	establish or strengthen as with new evidence or facts
misbehave badly; act in a silly or improper way	admit as valid
keep or maintain in unaltered condition; cause to remain or last	supply with necessities and support
	provide with nourishment
	be the physical support of; carry the weight of
	lengthen or extend in duration or space