If someone is described as having come-hither eyes, it means their eyes are seducitve or alluring. If you tell a horse to come hither though, what would you expect it to do?

The word hither [ˈhɪðə / ˈhɪðɚ] is a literary or archaic word that means to this place, to here or over here. So if you tell a horse to come hither, you’d expect it to come towards where you are, but this command actually means move to the left, apparently [source].

Hither comes from Middle English hider / hither (to here), from Old English hider (to here), from Proto-Germanic *hidrê (to this place, to here, hither), from *hiz (this) and *-drê (directional suffix) [source].

Related expressions include:

• behither = on this side of (rare, obsolete)
• hither and thither = to here and to here, one place after another, in different directions, in a disorderly manner
• hither and yon = in, at or to various places (dated, literary)
• hithermost = nearest to this side (archaic)
• hithertofore = heretofore, so far, thus far (rare)

What about thither? It means to that place, or to that point, end or result, and is used mainly in the expression hither and thither, and in legal language [source].

There’s also whither, which means to what place, where, to what cause, to which place, in or to any place to which [source].