Nouns

(n)thruma thrumming sound“he could hear the thrum of a banjo”

Verbs

(v)hum, thrumsound with a monotonous hum
(v)strum, thrumsound the strings of (a stringed instrument)“strum a guitar”
(v)drum, beat, thrummake a rhythmic sound“Rain drummed against the windshield”, “He drummed his fingers on the table”