unbacked

Lacking backing or support.

Not having a back.

Never having been ridden, as a horse.

Not having been backed; not taught to bear a rider; unbroken.

Unsupported; left without aid; unaided; in sporting, not supported by bets: as, an unbacked horse.

Not moved back or backward.

Never mounted by a rider; unbroken.

Not supported or encouraged; not countenanced; unaided.

Having no back

Having no (or few) backers