It's always interesting to hear where people draw lines in their complaints about overloading things. I remember for about 4 years after Go came out, people complained that it overloaded the name of the board game. No one cared that they both overloaded the verb though. Similarly, no one was upset that Python overloaded a kind of snake (yes, I know Python comes from "Monte Python") or that Rust overloads iron-oxide or Ruby overloads the gemstone or etc.

Is there a tool that allows for checking such name clashes, ideally by specifying the domain to see how close you are?

You mean like a web search engine? A quick search on "gio lib" shows a wiki for Gtk's GIO as the first result. You might narrow down the search adding domain-specific keywords to it, like "gio lib golang" to find something like this - https://github.com/vlorc/gioc (completely different field and name, but still can be found).

Having worked with GIO just yesterday I've got to say that the name GIO on it's own is not great in this modern age of the internet.

Because searching "gio menuitem" returns a lot more pizza than development docs :). Prefixing my search request with glib (which gio is a part of) solved that for me.

In that particular case a web search works, sure. But for most name clashes that I see, it's often tools that are well known in some domains but not so much in others.

Yeah, normally I wouldn't care about name clashes for unrelated tools but since GIO is part of GTK and specifically for writing cross-platform GUIs I think it becomes confusing again.