Maybe I got out of bed the wrong side today, but I'm starting to think these threads are started so that the poster can demonstrate their superiority to the rest of us.
Don´t know which effect getting out the bed the wrong side has on you - but if it has the effect of prompting you to engage in making unfavourable assumptions about the motives and intents of other people, then yes, you probably got out of the bed the wrong side today.
If there is a clear and simple, broadly agreed on definition of these terms, why not just give them?
So you'd have no idea what message the speaker is trying to convey when using these words?
I have no
clear idea. I have the idea that he is trying to make some sort of negative or positive value statement. What I do seem to understand is "I like it / I don´t like it" (although sometimes people even call things they like "immoral").
That´s not a good basis for a discussion, for neither of us.
If someone says "murder is wrong"
...he is just being tautological.

Whilst if he says "This instance of homicide is murder (or: wrong)"...
I think we can take it to mean; "I've weighed it up in my head, and I believe that generally murder is overall undesirable to society for many reasons, the reasons which should pretty much self explanatory"
Several problems here.
Of course we
can take it to mean that. However, we can not be sure that he means that - because oftentimes the way these words like "moral" and "ethical" are used implies that the speakers mean something different or beyond that.
There are a lot of much less ambiguous terms out there that would allow everyone who wants to convey a clear message to do so.
Any addendum to an explanation/definition to the effect of "It should be pretty much self-explanatory" tends to increase my confusion rather than decreasing it. A person saying "this is immoral" omits the relevant portions of his message. He neither gives me the reasons why he arrived at this unspecific negative value judgement, he doesn´t give me the information in regards to what/whom he considers it negative, he doesn´t communicate the perspective (his own, that of society - which? -, god´s, an assumed universal agreement, a natural force....?), he doesn´t tell me anything about the purpose of his considerations, and he doesn´t give any information about the implications that something being immoral has in his view.
I find myself in the position of having to read all the potentially significant portions of his intended message
into one word. That´s not a good start.
Maybe you could make an argument that using the words you listed is a misuse of language or something. I do know where you are coming from, I just don't think it really matters that much.
Where I come from, in verbal communication the meaning of the words used and understood (and a mutual effort of striving for a congruence of both) is
all that matters.
Btw. I´m just reading a great book on this topic that pretty much sums up where I am coming from:
Paul Watzlawick: How Real Is Real - Confusion, Disinformation, Communication