asthenic /-thenˈik/ adjective

1. Of or relating to asthenia
2. Lacking strength
3. Of a slender body type, narrow-chested, with slight muscular development (anthropology)
4. (of, or characteristic of, a person) belonging to a type thought prone to schizophrenia, having a small, light trunk and disproportionately long limbs (psychology)

A person of asthenic type

asthenosphere /-thenˈə-sfēr/ noun (geology)

The upper mantle of the earth, a shell lying below, and softer and more readily able to yield to persistent stress than, the lithosphere