Dikaio-, not so forensic
The Dikaio- words [dikaiosune (righteousness), dikaios (righteous), dikaioo (justify, set/do/make/become right), dikaiosis (justification, process of setting/making/becoming righteous), dikaioma (righteous acts)] are fairly important in biblical exegesis and theology.
Sometimes people talk about how the Dikaio- word group can be used in a "forensic" sense (ie legal, law-court language). Certainly this word group was sometimes used in law courts in the ancient world. There's nothing wrong with observing that. But, I was reminded with a shock recently while browsing the internet that some people actually think that the Greek word group itself has to do with law-courts and takes its meaning from a law-court setting and paradigm. In other words, they think that wherever we see a sentence containing a word from this group we ought to start thinking about a law-court setting. As these people read the bible wherever they see a Dikaio- word a law-court pops up in their minds.
The main trouble with this notion of the Dikaio- group as an "intrinsically forensic" word is that it is just utter crap. The vast majority of the uses of the word in both classical literature and the bible have nothing to do with law-courts. The Dikaio- word group is about morality. So it comes in useful sometimes in law-court discussions because law-courts generally try to discriminate the those who have done right from those who have done wrong and then do something about it.
In English, for example, we can talk about "guilty" and "innocent" people. Law courts use these moral terms precisely because they are interested in investigating the pre-existing moral status of individuals and subsequently announcing their findings. People do not become guilty of their crimes just because the court announces them guilty - rather they were already guilty or innocent prior to being tried and it is the court's job to search out and ascertain the truth. It is utter nonsense to talk of a judge making a person morally innocent by declaring them innocent. If the court gives the wrong verdict, the we would say "the judge got it wrong". In other words, the moral meaning of these English words is the primary one and the law-court usage is secondary and contingent on that moral meaning.
It is the same in Greek. "Dikaiosune" refers to morality / righteousness / virtue / goodness, and the "dikaios" are the good/virtuous/moral/righteous people, and so forth for the rest of the Dikaio- group. While such language can be useful in legal discussions, it is getting the cart before the horse to think that such language makes it a legal discussion. Use of such language makes it a discussion of morality and ethics. Moral language can be used in a judicial context of course, but the use of morality-related language doesn't make the context a judicial one. I shudder to think the sort of havoc screwing up the meaning of such a basic, central, and simple word makes to their exegesis and theology. But sadly, the linguistic nonsense of Dikaio- as intrinsically forensic terminology seems to propagate itself precisely because people like the theology it results it - ie the claim seems to be made for theological reasons rather than due to actual evidence for the view.
Pointless historical speculation: As far as I can tell, know or guess, the idea that Dikaio- is intrinsically forensic is a hangover from when the Latin Vulgate crossbreed with the origins of the modern judicial system half a millennia ago. The coincidence that the then-millennium-old Vulgate's Latin terminology happened to match with the then-current Latin judicial terminology was at the time projected back onto the underlying Greek.