Peckover whistled uncomfortably and tunelessly through his clenched teeth; a more elaborate expression of feeling he did not feel equal to.
"A Poached Peerage"
William Magnay
Arthur, who was stropping a razor and whistling tunelessly, raised his eyebrows.
"The Man Upstairs and Other Stories"
P. G. Wodehouse
He laughed at her and went his way, humming tunelessly after his own peculiarly volatile fashion.
"The Way of an Eagle"
Ethel M. Dell