whicker

/ˈwɪkər/
verb
  1. To make a soft, high-pitched neighing sound, as a horse does.
    • She heard a gentle whicker from the pony as she offered it an apple.
    • In the stable, the foal whickered to its mother.
    • The horse whickered softly when it saw its owner approaching.
Synonyms
noun
  1. A soft, high-pitched neighing sound made by a horse.
    • A quiet whicker came from the dark stall.
    • The horse's whicker was barely audible over the wind.
    • He recognized the friendly whicker of his favorite mare.