Available Definitions:
1) n. - A horse for riding or driving; a nag; a pony.
2) n. - A horse or pony kept for hire.
3) n. - A carriage kept for hire; a hack; a hackney coach.
4) n. - A hired drudge; a hireling; a prostitute.
5) a. - Let out for hire; devoted to common use; hence, much used; trite; mean; as, hackney coaches; hackney authors.
6) v. t. - To devote to common or frequent use, as a horse or carriage; to wear out in common service; to make trite or commonplace; as, a hackneyed metaphor or quotation.
7) v. t. - To carry in a hackney coach.