the GNU version of the Collaborative International Dictionary of English
n. The state of being tired, or weary.
The Century Dictionary and Cyclopedia
n. The state of being tired; weariness; exhaustion.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. temporary loss of strength and energy resulting from hard physical or mental work
Word Usage
""Chalking it up to moodiness or trouble at work or tiredness is pretty common," says Carrie Bearden, PhD, associate professor in residence of psychiatry and behavioral sciences and psychology, at the David Geffen School of Medical at UCLA."