From Catholic Exchange and Eric Scheske:

The absurd, Camus said, is the state of existence that is every man’s lot
because nothing corresponds to his highest yearnings. In order to understand what Camus is saying, consider how ridiculous it would be if there was no such thing as food, but we had an appetite for it. At some point someone would become aware of the odd juxtaposition of appetite and no food, and say, “What’s going on here? Why do we have an appetite if there is no such thing as food to satisfy it?” That’s the same thing Camus said about man’s desires and dreams. Every man hopes, but there is nothing to satisfy his hopes. Man naturally harbors desires, but there is nothing to respond to them. That, Camus said, is absurd.

And for an agnostic/atheist, he’s right. We’re full of yearnings, of desires for something higher, of hope for eternity. But what do we get in return? Disappointment, pain, and death.

Things are philosophically tough for an atheist.

Of course, from a religious standpoint, things are not at all absurd:

Moreover, those yearnings are there for a reason: they correspond to reality. The mere fact that we yearn for permanency — for eternity — points to
the fact that permanency exists. And because we know nothing material lasts forever, the permanency must be spiritual.

Now, having lived an absurd life for many years, I know it is very easy to know the solution and not so easy to live the solution. It is very easy to know that faith, hope and charity are the key to happiness, but it is not so easy to have faith and hope. And even more difficult to have charity, even if one does have faith and hope.

But, to deny oneself the pure joy that comes with having faith and hope and exercising charity is…absurd.