"Happiness: the quality or state of being happy."
Happiness is something that everyone experiences differently throughout their lives. So how can happiness be defined as something so simple?
To be happy. That's what everyone really, truly, wants to be. Some people want to be doctors, lawyers, beauticians, others: they want to be happy. Happiness doesn't come easy for everyone though. When you find yourself finally finally happy, something or someone comes into your life and tears it all down. Bringing you into that dark hole you never thought you'd fall back into ever again. That hole you climbed out of with all the force you mentally had, only to come up to the surface completely broken, with your mind resetting into the pessimistic state you hate thinking in.
You will be happy again.
It doesn't happen over night. Happiness is a skill that everyone is continuously learning how to achieve for themselves. You learn how to deal with certain obstacles that life throws at you. You learn what you enjoy and what you need to stay away from. Your mind may be constantly telling you, "no," but you'll get through it. No matter what is happening, no problem is too small and do not feel like you cannot get help from someone. The littlest problem is still a problem and it is worth discussing about.
To be truly, unconditionally happy: be who you are.
You are you for a reason. Whether you know that reason or not, there is still a reason. It's okay to feel low about things. It's okay to feel insecure about yourself. You wouldn't be human if you weren't insecure at times, but you'll get through it. The road to happiness is not a short one. It's not a road you can just simply speed through. Find yourself. Find you who want to be and who you are and stay true to what you believe in. The people who love you will support you through anything and those who don't shouldn't be in your life anyways.
"The quality or state of being happy," will never truly define the term "happiness" but it will be the closest definition that we can link to a concept so broad. A concept that everyone in their life tries to understand and reach for themselves.