Mike Burke wrote:
Long definition: unconcealed, true, true in fact, worthy of credit, truthful.
So "worthy of credit" (i.e. "valid," "admissible") is within the semantic range of the word.
No, "valid" and "admissible" are not within the semantic range of the word. You are trying to make a confusion between the context in which a testimony is given and the internal nature of that testimony.
As a beginner, you will be going through the process of acquiring a sense of how language works. Let me answer you briefly from that point of view. Your question really only touches very lightly on the Greek.
Questions about the semantic range of the Greek word assume understand the English. The two words you are asking about are special words, whereas the simple word you are learning as a definition; "true" is a general word. [FYI the other word "unconcealed" is an etymological definition - it is to help you understand the internal structure of the Greek word - we don't
use such words in English translations.]
The word "admissible" is used in special ways in English. The word is used in a specific location -a court room - in relation to a testimony.
We can ask some basic questions in regard to "true", "admissible" and "testimony".
Could a testimony be admissible and not true? [yes, if somebody were lying.]
Could a testimony inadmissible and true? [Yes, if the legal system didn't accept that that person could give evidence (perhaps a slave or non-citizen)]
Could a testimony be inadmissible and not true? [Yes, if a slave or non-citizen was going to lie]
Your question; Could a testimony be true and admissible? [Yes, if a free citizen were telling the truth]
IN FACT, your question is not about Greek. It is about the relationship between a "true testimony" and an "admissible testimony".
Linguistic awareness is something that you, as a beginner, need to develop, it's true, but your Greek is not up to a standard at whicb you can question, much less rewrite definitions for Greek words.
Just memorise the most basic definitions posssible.
Οὐκ οἶδα τί λέγεις. ¯\_(ツ)_/¯