1Lacking the attributes or accomplishments required to qualify for something; incapable of attaining the necessary qualifications.
2That cannot be characterized as having specific qualities; indefinable; indescribable.
3Indescribably bad; unspeakable; objectionable.
Common in the 19th century. Now rare.
4That cannot be modified, limited, or restricted; not open to qualification.
Mid 18th century; earliest use found in Roger North (1651–1734), lawyer, politician, and writer. From un- + qualifiable.