What is "to whistle off"

Whistle \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.

   1. 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.

   2. 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.''
      --Nares.