Is there such a thing as an absolute, when related to good, evil, true or false?

absolute: "Perfect in quality or nature; complete."

I believe there are no absolutes of abstract concepts.

We have absolute zero and the speed of light that refer to limitations of physics. I think they're a boundary of sorts - they may be broken sometime, in much the same way as we used to believe that the speed of sound was a speed limit.

What I'm referring to is absolute quantities of abstract concepts. Truth, Good, Evil, Falsehood, Justice that kind of thing.

I think there's never an absolute of an abstract concept. It's never the case that any one act is absolutely good.

Simply because the measures of such abstract concepts are subjective - they're measured relative to their impact and intended impact on others.
If I cut someone up whilst driving, then it's a little bad. If I do so and cause a major accident and the other driver ends up dead, then it's worse. If I did so and intended to cause a major accident, then it's worse still.

I believe that absolute concepts are a human invention. Perhaps as a tool for manipulation, but nevertheless arbitrary divisions.

There are those that will suggest that whilst mankind may not know the absolutes, there's a God or Gods that set the line, and we've got to try to live up to it.
I'd see it that it matters little either way. The difference between incomprehensible and non-existant absolutes is irrelevant.

All measurements of such abstracts are a relative, or subjective measure. You can see two things, and say overall, one was more true than the other. You'll not see anything absolutely true though.

So all we need do is decide where we stand on such things. And then do our utmost to enforce it. That's about all that can be done. Maybe one gets measured against absolutes at the end of their life. Maybe they don't. Either way, you live according to your choices.

Edit: Modified examples slightly due to karen2205's comment.