山犬

Etymology
Compound of.

Noun

 * 1)  an apparition of a dog that may appear to travelers on mountain roads, and that may be either friendly or murderous to travelers
 * 1)  an apparition of a dog that may appear to travelers on mountain roads, and that may be either friendly or murderous to travelers
 * 1)  an apparition of a dog that may appear to travelers on mountain roads, and that may be either friendly or murderous to travelers

Usage notes
Biologists consider the Japanese yamainu to be a feral dog, distinct from the wolf. The conflation with the sense is due to some confusion in general usage. See more on Wikipedia.