hum vs thrum

hum and thrum both are nouns.

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

As verbs, hum and thrum are synonyms defined as:

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

hum (verb)	thrum (verb)
sing with closed lips	make a rhythmic sound
make a low continuous sound	sound with a monotonous hum
sound with a monotonous hum	sound the strings of (a stringed instrument)
be noisy with activity