1. the quality or state of being happy.
2. good fortune; pleasure; contentment; joy.
1, 2. pleasure, joy, exhilaration, bliss, contentedness, delight, enjoyment, satisfaction. Happiness, bliss, contentment, felicity imply an active or passive state of pleasure or pleasurable satisfaction. Happiness results from the possession or attainment of what one considers good: the happiness of visiting one's family. Bliss is unalloyed happiness or supreme delight: the bliss of perfect companionship. Contentment is a peaceful kind of happiness in which one rests without desires, even though every wish may not have been gratified: contentment in one's surroundings. Felicity is a formal word for happiness of an especially fortunate or intense kind: to wish a young couple felicity in life.
Origin: 1520-30; happy + -ness
Now YOU come up with a sentence (or fic? or graphic?) that best illustrates the word.