astheno-, asthen-; -asthenia, -asthenic

Instability or loss of tone in the vascular system.

Spasmodic variability in the tone of blood vessels.

Strengthening or invigorating.

An abnormal lack or loss of strength and energy: "The asthenia of the man showed his weakness and lack of vital forces which resulted in debility and feebleness."

1. Relating to or exhibiting asthenia; weak.
2. Having a slender, lightly muscled physique.

1. A period of reduced metabolic activity (chemical and physical processes involved in the maintenance of life).
2. Either the condition of an inactive larva not yet metamorphosed to a pupa or autointoxication, particularly among insects.

Sluggish pupillary light reflex.

An unexplained fear of weakness; such as by losing one’s physical, social, or some kind of political control. It may also be a fear of fainting.

Eye weakness, or strain; often causing a headache, ocular discomfort, dimness of vision, etc.: "His asthenopia included such symptoms as fatigue, red eyes, eye strain, pain in or around the eyes, blurred vision, and occasional double vision."

A condition in which one has weak feet.

1. A reference to the zone beneath the earth's surface that lies beneath the lithosphere and consists of several hundred kilometers of weak material that readily yields to persistent stresses: "According o the theory of plate tectonics, the Earth's lithosphere is a rigid outer layer that moves slowly over the weaker asthenospheric zone."
2. Etymology: from Greek astheneia, "weakness"; which consists of a-, "without" + sthenos, "strength" + -spheric, "being around" or "a zone".

1. A condition of impairment or weakness caused by overwork.
2. Etymology: from Greek ergon, "work" + asthenos, "weakness".