Not having been banked. / Not served by a bank. / (rail transport, rare) Of a train, not having the assistance of a banker (etymology 3) when climbing a steep grade (or bank).

simple past tense and past participle of unbank

Not bankable.

Third-person singular simple present indicative form of unbank

(transitive) To remove a bank from; to open by, or as if by, the removal of a bank. / (transitive) To make (a fire) burn up by raking off the ashes from the top, opening draughts, etc.

present participle of unbank