Definition: a deficiency or failing, especially in a neurological or psychological function.
The word was encountered in “The Natural Fix for A.D.H.D.” written by Richard A. Friedman. The author uses this word to explain what A.D.H.D abbreviates for, “Attention deficit hyperactivity disorder”.
I knew what A.D.H.D was, I just didn’t understand what deficit meant which is apart of defining the type of disorder it is. This word has other definitions but all surround the same definition of something “failing”