hyposthenuria

[hī-pŏs′thə-nurē-ə]
n.
  1. Excretion of urine of low specific gravity due to an inability of the tubules of the kidneys to produce concentrated urine.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.