Strum
\Strum\, v. t. & i. [imp. & p. p.
Strummed; p. pr. & vb. n.
Strumming.] [Probably of imitative origin. Cf.
Thrum.] To play on an instrument of music, or as on an instrument, in an unskillful or noisy way; to thrum; as, to strum a piano.
[1913 Webster]