Strum – Play a stringed instrument, such as a guitar, by moving your thumb or a small piece of plastic repeatedly across the strings
The strings would hum (strum) when he stroked his thumb across the strings.
Examples of strum in a sentence
He would strum the guitar very aggressively, despite constantly being told not to by his tutor.
The second the musician began to strum the guitar, the crowd went quiet so they could hear him play.
She had developed a callous on her thumb from how often she would strum her bass guitar.