1) A group of people who enjoy My Little Pony and go on 4Chan. Horsefuckers aren't necessarily cloppers, and usually are against bronies, for the majority being newfags.
2) A person who fucks horses
1) There's an anon on the /mlp/ thread who keeps a BlueFast toy in a jar of his own cum
2) A man was arrested a couple months ago fucking a horse. Heh heh. Horsefuckers.
About the age of thirty Jack became a horsefucker. Jack later met Jill, who enjoyed blowing horses, so they formed a team that went from town to town performing disgustingsexual acts with nags, fillies and stallions. The two finally settled in Durango, Colorado, where they run a greasy flap jack house.