Sorry, OP, I would come over and rescue both of you from this situation, but I don't know where you live!
A spider, especially a large one, out in view in the middle of the day, definitely does not want to be there, either. It could be injured, or ill, or was wandering around last night looking for a mate, and lost track of time. If you leave it alone, it will wander off as soon as it thinks it's safe, and hide in the nearest hole in your skirting boards. It doesn't want to interact with you as much as you don't want to interact with it!
You haven't said what kind of large spider. If it's one of those "daddy longlegs" that are basically transparent, then they belong in your house, and will try to eat all your other spiders. If it's a large Tegenaria, then it's also a house spider, but they will also live in sheds or fences.
If you can't wait, just carefully put a glass over it, slide a postcard or something underneath (careful of its legs), and throw it outside.
It's waiting for you to go away, and until it doesn't feel any more vibrations, it will stay still and pretend you don't see it. That's its only defence.
Please don't kill it.
I love spiders. Especially tiny jumping spiders.
ed. for spelling