To divert vehicles or travellers means to make them follow a different route or go to a different destination than they originally intended. You can also say that someone or something diverts from a particular route or to a particular place.

To divert money or resources means to cause them to be used for a different purpose.

To divert a phone call means to send it to a different number or place from the one that was dialled by the person making the call.

If you say that someone diverts your attention from something important or serious, you disapprove of them behaving or talking in a way that stops you thinking about it.