1. A lack of order or regular arrangement; confusion.
2. A breach of civic order or peace; a public disturbance.
3. An ailment that affects the function of mind or body: eating disorders and substance abuse.

1. To throw into confusion or disarray.
2. To disturb the normal physical or mental health of; derange.

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.