The Collaborative International Dictionary
Whistly
Whistly \Whist"ly\, adv. In a whist manner; silently. [Obs.]
Wiktionary
whistly
Etymology 1 adv. (context obsolete English) silently Etymology 2
a. (context informal English) Making a whistle sound.
Usage examples of "whistly".
S'reee said, giving Nita's name a whistly whalish intonation, "but sisters too, by blood exchanged.