The prisoner made an abortive attempt to escape from the jail.

Courageous : not deterred by danger or pain; brave.
Futile : incapable of producing any useful result; pointless.
Illegal : contrary to or forbidden by law, especially criminal law.
Furtive : attempting to avoid notice or attention, typically because of guilt or a belief that discovery would lead to trouble; secretive.
Abortive : failing to produce the intended result.

Synonym of Abortive is Futile