You probably know about the 'Jesus Fish' symbol, and how it supposedly came from the first letters (in Greek) of Jesus Christ, Son of God, Saviour - that spelled something that sounded like the Greek word for 'fish'.
I was reflecting on the extent to which this is a helpful summary of Christianity - as I understand it. One can see that the word Christ is of compelling importance only to ancient Jews, as referring to their anticipated Messiah, a divinely-anointed king - but that this has no meaning or validity to a modern secular person. However, 'Jesus Christ' does make clear who we are talking about - not just some Spanish footballer called Jesus... So we can keep Christ as an identifier!
Son of God? Yes, but so are we all. Jesus is divine, and he is not identical-with 'God the creator'- but this kind of subtle theological consideration is probably not an appropriate focus for a brief summary of the importance of Jesus. Better to leave-it-out.
Then there is the word Saviour... Saving from what? is the first question. And a one word answer is Sin - but by Sin is properly meant something close to what we would say by Death; rather than by what most modern people mean by Sin, which is moral transgression, the thinking and doing of evil. Because of this moral/ ethical understanding of Sin, modern people don't regard it as the kind-of-think that one can be saved-from...
Yes, there is the idea that we need saving from 'Original' Sin - but this was supposedly inflicted by God on Adam and Eve and all descendants as a form of Justice; and that kind of Justice seems (on the face of it) un-just...
And anyway, it makes for a rather strange kind of double-negative theology if Jesus's role was to save us from a punishment inflicted by his Father. It sound close-to: good-Jesus saves us from evil-Father...
In sum: If Jesus is primarily about saving us from the consequences of sin-evil, and these consequences are divine in origin; then we are (merely) being saved from God, by God. I know there are theological explanations for this - but at a common sense level it would strike a modern person to have been better, easier, quicker for God not to condemn all Men in the first place.
So, if Saviour is not a satisfactory summary-word for the work of Jesus; is there a better one?
Yes! In the Fourth Gospel we are told several times and in several ways that Jesus gave us Life Everlasting, Life Eternal. Which means that after 'biological death', instead of everybody going to the demented, ghostly half-life of 'Sheol'; Jesus has brought the gift of resurrection to a Heavenly life, as divine children of God, in Heaven.
This Gift is given to all who follow Jesus through death.
And to follow Jesus we need to love him, have faith in him, trust him - as sheep follow a Good Shepherd.
So Jesus is, mostly, the Giver of Life.
Now, any such brief summary is bound to lead to questions, to require elucidation. And Giver and Life both invite elucidation. But I think these explanations can briefly and simply be provided, along the lines expressed above.
Such obvious questions include - why can't God give Everybody this kind of Life. Why only those who love Jesus?
And the answer is that some people, perhaps most people, do not want what Jesus offers; and the reason why they do not want it, is where the more familiar idea of Sin as moral transgression comes-in.
Another obvious question is why we can't simple be born directly into Heaven? Why all this 'tedious mucking about' in mortal life?
And that answer to that has to be along the lines that this is the only way it can happen, it is the way things-work. Evidence is that Jesus himself had to attain resurrection via mortal life; and so we must do the same.
I think other questions can be given similarly brief and comprehensible answers.
So that is my suggested alternative to ICHTHYS: Jesus Christ, Giver of Life.