(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).
That cannot be graded.
Any adjective that is not gradable.
Tenuous; rarefied; of low density or thin consistency.
Barely noticeable, not obvious, indistinct.
Cleverly contrived.
Cunning, skillful.
Insidious.
Hard to grasp; not obvious or easily understood.