If you retake a course or an examination, you take it again because you failed it the first time. I had one year in the sixth form to retake my GCSEs. Retake is also a noun. Limits will be placed on the number of exam retakes students can sit. = resit
If during the making of a film there is a retake of a particular scene, that scene is filmed again because it needs to be changed or improved. The director, Ron Howard, was dissatisfied with Nicole's response even after several retakes