I was chiding you, absolutely! But I will provide some context for my comments so that we can see where each other are coming from.

I did figure you were asking sincerely "exist" to be defined, but deny that the word in this context can be defined to any avail since it has a near tautological use. Things can exist in many ways: they can exist in the mind, or they can exist independent of the mind (mind-independent), or they can exist in the mind of God, or as a fact about the world. A thing can exist contingently or necessarily, a priori or a posteriori, as an analytic or a synthetic truth.

I was going to say that these technical terms don't really apply to the argument - that simple ordinary language reveals that there must be something for us to talk about anything. But on further reflection you are right. It is important to define in what way this something-that-must-exist exists.

However, I don't believe conventionally defining the word exist as you requested does anything more than "pass the buck" as you say to another term. I say that the meaning of a word is determined by how it is used. Sometimes an author or a community will be very specific about its use and it is a technical term.

Agreement about how to discuss language is key to continuing rational argument. It follows that we must agree about what it is we want when we ask for definitions too! My understanding generally comes from Wittgenstein (I highly recommend Ray Monk's biography on him!). This essay by David Foster Wallace is full of humor and, brilliant man that he is, explains quite a bit about linguistic theory in the process!

In sum, there is still room for discussion about what the phrase "something must exist" actually entails. I was too dismissive; I generally associate the quest to ever define with a fundamental misunderstanding about how language works.

Is it solipsistic in here or is it just me?!