How can there be any widely accepted definition of happiness?
Doesn’t if depend entirely on individual circumtances?
The ingredients of “happiness” can—and do—vary tremendously according to who and what and where and how you are.
Probably there can be agreement on the adjectives and adverbs of “happiness.” But try to name the circumstances that contribute validity to the definition.
One person’s idea of happiness can be another’s description of misery. Our needs are not the same. Nor are our values, our desires, our goals.
So you can say what to you is happiness. And I can say what to me is happiness. And we may even agree on some of the definitions or ingredients, but few people can agree totally on what they each mean by “happiness.” It’s too personal a thing for universal agreement.