It's very likely to be a brushless motor. They have electronic commutation using an ESC circuit. If you are lucky you'll be able to disconnect the motor from its ESC and test it using another one (you can actually buy ESC units for testing on eBay). Failed motor is pretty unlikely and "cactus" if it is, but a failed ESC is potentially fixable if you know what you're doing. Or you could possibly get a replacement ESC which will fit inside the drill, or at least be able to use the motor for something else. Worst case scenario is it's a sealed lump and you can't get at anything.
But before you do any of that, see if power is getting from battery to switch, switch to electronics, electronics to motor - also test the 0v return path which is also possible (though unlikely) to fail - it could prove to be just a wire that's broken off from all the vibration.
If it is actually a brushed motor, it's most likely the brushes have worn out. I've had this with 2 power tools last week, worked intermittently for a bit, then packed in altogether. Easy enough to replace and cheap if you get generic ones.
I had a Wolf drill briefly in the '90's. Got it for £5 from a s/h shop, absolutely brilliant. Very sad to have parted company with it.