n 1  :  a displacement downward or inward < of the jaw>   2  :  an act of depressing or a state of being depressed: as  a (1) :  a state of feeling sad (2) :  a psychoneurotic or psychotic disorder marked esp. by sadness, inactivity, difficulty with thinking and concentration, a significant increase or decrease in appetite and time spent sleeping, feelings of dejection and hopelessness, and sometimes suicidal thoughts or an attempt to commit suicide  b  :  a reduction in functional activity, amount, quality, or force < of autonomic function>  < of erythrocytes and platelets>  .
 
 
 
Published under license with Merriam-Webster, Incorporated.  © 1997-2024.