busyness vs hum

busyness and hum both are nouns.

Word	Noun	Adjective	Verb	Adverb
busyness	Yes	No	No	No
hum	Yes	No	Yes	No

As nouns, busyness and hum are synonyms defined as:

busyness and hum: the state of being or appearing to be actively engaged in an activity

busyness (noun)	hum (noun)
the state of being or appearing to be actively engaged in an activity	a humming noise
	the state of being or appearing to be actively engaged in an activity