A cruiser motorcycle is a big bike that is designed to be comfortable and easy to ride for long periods of time.
It has a low seat, so it's easy for your feet to reach the ground when you stop, and it has a wide, stable base, so it won't tip over easily.
The handlebars are set high up, so you don't have to lean forward and strain your back, and the foot pedals are set forward, so you can stretch out your legs and relax while you ride.
Cruisers also have big, powerful engines that can easily handle highway speeds and long trips.
Overall, they're great for cruising around, enjoying the scenery and feeling the wind in your face, without having to worry about getting tired or uncomfortable.