A common definition of reality is the world or the state of things as they actually exist, as opposed to an idealistic or notional idea of them.

It seems simple enough but determining the existence of something, and what that entails, has a subjective component and therefore defining what is real can become different depending on individual perspective (although this flies in the face of the definition.)

Existentialism

Soren Kierkegaard was a philosopher who proposed that each individual—not society or religion—is solely responsible for giving meaning to life and living it passionately and sincerely, or “authentically”

In essence, this could be broadly interpreted as meaning we create our own reality.  How we give real meaning to our lives is founded on our self-creation.

We create ourselves and live within our self-creation.  This becomes our reality and the essence of our existence.  This does not mean we can ignore things as they actually exist, however; we can perceive them in the context of our self-actualization.

So Is Anything Real?

If there is broad acceptance by everyone that a thing actually exists than it does.   What that existence means and the impacts of it can be open to analysis and interpretation.

A single reality only exists for the individual but out of convenience and for practical purposes general consensus of reality across a population is needed.

Your own reality is constrained by outside forces.  For example, if you believe you have the ability to survive underwater with breathing assistance, the constraints of reality will intrude in a very real and deadly way.