aphasia(n = noun.state) - inability to use or understand language (spoken or written) because of a brain lesion;
is a kind of brain disease, brain disorder, encephalopathy
has particulars: acoustic aphasia, auditory aphasia, word deafness, associative aphasia, conduction aphasia, global aphasia, total aphasia, ataxic aphasia, broca's aphasia, expressive aphasia, motor aphasia, nonfluent aphasia, amnesic aphasia, amnestic aphasia, anomia, anomic aphasia, nominal aphasia, transcortical aphasia, alexia, visual aphasia, word blindness, fluent aphasia, impressive aphasia, receptive aphasia, sensory aphasia, wernicke's aphasia
Derived forms adjective aphasic₂, adjective aphasic₁

   Loss of the power of speech, or of the appropriate use of words, the vocal organs remaining intact, and the intelligence being preserved. It is dependent on injury or disease of the brain. [1913 Webster]

aphasia, n. Med. the loss of ability to understand or express speech, owing to brain damage.

Derivative:
aphasic adj. & n.

Etymology:
mod.L f. Gk f. aphatos speechless f. a- not + pha- speak

acoustic aphasia, amnesic aphasia, amnestic aphasia, anomic aphasia, associative aphasia, ataxic aphasia, auditory aphasia, broca's aphasia, conduction aphasia, expressive aphasia, fluent aphasia, global aphasia, impressive aphasia, motor aphasia, nominal aphasia, nonfluent aphasia, receptive aphasia, sensory aphasia, total aphasia, transcortical aphasia, visual aphasia, wernicke's aphasia