ataxia

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Loss of the ability to coordinate muscular movement.

from The Century Dictionary.

• noun In pathology, irregularity in the functions of the body or in the course of a disease; specifically, inability to coördinate voluntary movements. Also ataxy.

from the GNU version of the Collaborative International Dictionary of English.

• noun obsolete Disorder; irregularity.
• noun archaic, archaic Irregularity in disease, or in the functions.
• noun archaic The state of disorder that characterizes nervous fevers and the nervous condition.
• noun (Med.) Loss of coordination in the voluntary muscles, especially the limbs; an inability to coordinate voluntary muscle movements; it results in unsteady movements and a staggering gait. See also locomotor ataxia, an ataxia which occurs when attempting to perform coordinated muscular movements.
• noun See Locomotor.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun pathology Lack of coordination while performing voluntary movements, which may appear to be clumsiness, inaccuracy, or instability.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun inability to coordinate voluntary muscle movements; unsteady movements and staggering gait