The American Heritage® Dictionary of the English Language, 4th Edition
n. A psychological disorder characterized by chronic fatigue and weakness, loss of memory, and generalized aches and pains, formerly thought to result from exhaustion of the nervous system. No longer in scientific use.
n. An ill-defined medical condition characterized by lassitude, fatigue, headache, and irritability, associated chiefly with emotional disturbance.
the GNU version of the Collaborative International Dictionary of English
n. A condition of nervous debility supposed to be dependent upon impairment in the functions of the spinal cord.
The Century Dictionary and Cyclopedia
n. In medicine, nervous debility; nervous exhaustion.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. nervous breakdown (not in technical use)
Word Usage
"While the term neurasthenia is becoming daily more familiar to the general public, it is being, on the whole, used, except as a convenient handle, rather less among neurologists."