Sad
Part of speech: adjective
Definition: Sated, having had one's fill; satisfied, weary. Steadfast, valiant. Trustworthy, serious, grave. Feeling sorrow; sorrowful, mournful. Appearing sorrowful. Causing sorrow; lamentable. Poor in quality, bad, shabby. Unfashionable; socially inadequate or undesirable. soggy (to refer to pastries).
Example sentence: It doesn't hurt to feel sad from time to time.
Sorrowful
Part of speech: adjective
Definition: Of a person, full of sorrow; exhibiting sorrow; sad; dejected; distressed.Producing sorrow; exciting grief; mournful; lamentable; grievous.
Example sentence: When you are sorrowful look again in your heart, and you shall see that in truth you are weeping for that which has been your delight.