adjective
feeling or showing sorrow; unhappy.
Similar:
unhappy, sorrowful, dejected, regretful, depressed, downcast, miserable, downhearted, down, despondent, despairing, disconsolate, out of sorts, desolate, bowed down, wretched, glum, gloomy, doleful, dismal, blue, melancholy, melancholic, low-spirited, mournful, woeful, woebegone, forlorn, crestfallen, broken-hearted, heartbroken, inconsolable, grief-stricken, down in the mouth, down in the dumps
Opposite: happy, cheerful
While sadness is a normal, temporary feeling, depression is a persistent mood disorder that can significantly impact daily life and functioning, often lasting for two weeks or more and accompanied by other symptoms beyond just sadness.