"Unlimited retakes" means there is no limit or restriction on the number of times you can redo or retry something, such as a test, exam, or performance. Full definition
You are allowed unlimited retakes on your quizzes, and a total of one (1) retake on your final exam. (idrivesafely.com)
Pass all of them to officially complete the course, but if you don't pass the first time, there's nothing to worry about — we offer unlimited retakes on our exams. (idrivesafely.com)
Don't worry about passing the first time, though — students are offered unlimited retakes for their final exam. (idrivesafely.com)