whistle \whis"tle\, v. i. imp.  p. p. whistled; p. pr.  vb.
   n. whistling. as. hwistlian; akin to sw. hvissla, dan.
   hvisle, icel. hvimacsla to whisper, and e. whisper.
   root43. see whisper.
   1913 webster
   1. to make a kind of musical sound, or series of sounds, by
      forcing the breath through a small orifice formed by
      contracting the lips; also, to emit a similar sound, or
      series of notes, from the mouth or beak, as birds.
      1913 webster

            the weary plowman leaves the task of day,
            and, trudging homeward, whistles on the way. --gay.
      1913 webster

   2. to make a shrill sound with a wind or steam instrument,
      somewhat like that made with the lips; to blow a sharp,
      shrill tone.
      1913 webster

   3. to sound shrill, or like a pipe; to make a sharp, shrill
      sound; as, a bullet whistles through the air.
      1913 webster

            the wild winds whistle, and the billows roar.
                                                  --pope.
      1913 webster
see also:
whistled whistling whisper