Any adjective that is not gradable.
That cannot be graded.
(of an adjective) Describing a quality that cannot normally be varied because it is extreme (e.g. freezing), absolute (e.g. dead), or classification (e.g. nuclear).
An undistinguished, unexceptional person or thing.
An unmarked police car.
A species or other type of creature that has not been previously described or identified.
Without distinguishing qualities or characteristics.