Whis·tle, v. t.
1. To form, utter, or modulate by whistling; as, to whistle a tune or an air.
2. To send, signal, or call by a whistle.
He chanced to miss his dog; we stood still till he had whistled him up. --Addison.
To whistle off. (a) To dismiss by a whistle; -- a term in hawking. “AS a long-winged hawk when he is first whistled off the fist, mounts aloft.” --Burton. (b) Hence, in general, to turn loose; to abandon; to dismiss.
I 'ld whistle her off, and let her down the wind
To prey at fortune. --Shak.
Note: ☞ “A hawk seems to have been usually sent off in this way, against the wind when sent in search of prey; with or down the wind, when turned loose, and abandoned.”