Definition of unbacked:
(adj) :
Not supported or backed up (by someone or something).
(adj) :
Having no (or few) backers.
(adj) :
(not comparable) Having no back.
(adj) :
(photography, holography) (of a plate) Not having an antihalation backing.
(adj) :
(obsolete, not comparable) Of an animal: never having been ridden or not accustomed to being ridden; not (currently) being ridden.