Justice being defined in terms of the adjective 'just' does not constitute a circular reference, especially since 'just' doesn't typically reference 'justice' in its definition.
It doesn't seem tautological either since the words mean different things, especially with the negative sense being called out.

You put this topic in Logic section like it's the logic of the definition and not the language question that concerns you. In the end, all words must use other words to define them, and thus is circular in the end. Be interesting to find an alien dictionary and work out the language just from that, with no pictures or anything.

is the statement "Justice means nothing but what is just, indeed more in the negative sense than the positive, insofar as justice is that which is not unjust" circular reasoning, a tautology, or neither? — KantDane21

Neither. It is primarily nonsense in that the context ("unjust") depends on the primary assertion ("justice"). It's like saying "you'll know it when you see it."

However, that does not mean it is not valuable. The essence of language is its ability to communicate implications toward an experience. If language was only able to state what has been experienced, it would be of limited use as communication would be predicated on pre-existing experience when the value of language is its ability to communicate an experience that has not yet occurred.

I'm sorry, but isn't this supposed to be a mathematical philosophy page?

I'm sorry, but isn't this supposed to be a mathematical philosophy page? — alan1000

No, that's down the corridor with Mr Russell. They started half an hour ago. This is the hyperbolic crochet class.

Sorry, please wait while I gather my wool and my needles!
Although I suppose there is a mathematical aspect to the question: should justice be reducible to a strict logical formula, in the same way that all of mathematics can be reduced to a system of formal logic? And how might such a system be defined so as to allow justice to be tempered with mercy (essentially, extenuating circumstances)? Could that, in its turn, be reduced to a system of formal logic?

Aren't we just talking about apophatic verses cataphatic definitions?

A lot of information about the etymology/origin of terms only goes back so far.
There are also 'urban myth,' style claims which I have always found intuitively, probably have some truth behind them but I don't claim they are true. Examples include:
The word Justice comes from the Roman emperor Justinian 1st who rewrote Roman law.
The word sin comes from Naram sin, the King of the Akkadians who was disrespectful to the gods (the curse of Akkad) and the gods therefore destroyed his kingdom because of it.
The word evil comes from Eve and simply means those who behave like Eve and disobey god. I hope this one has some truth in it as it takes a lot of the power out of this word imo and helps show that god stories are just fables.

Folklore can be fun!

But not much use in proving mathematical propositions, I'm afraid.