Unhappiness

1. Not happy or joyful; sad or sorrowful: unhappy over his friend's departure.
2. Not satisfied; displeased or discontented: unhappy with her raise.
3. Not attended by or bringing good fortune; unlucky.
4. Not suitable; inappropriate: an unhappy choice of words.

1. sadness, depression, misery, gloom, sorrow, melancholy, heartache, despondency, blues, dejection, wretchedness, low spirits There was a lot of unhappiness in my adolescence.
2. discontent, dissatisfaction, displeasure, uneasiness, vexation, discontentment He has signalled his unhappiness with the government's decision.
Quotations
"He felt the loyalty we all feel to unhappiness - the sense that that is where we really belong" [Graham Greene The Heart of the Matter]
"Unhappiness is best defined as the difference between our talents and our expectations" [Edward de Bono]

Source

www.thefreedictionary.com