When it comes to describing someone who is taking an exam or test for a second time, there are several synonyms for the word "retaker" that can be used. Some options include "re-examiner," "repeat test-taker," "second-chance exam candidate," and "re-do test taker." Each of these terms conveys the idea that the person is taking the exam again after not passing on the first attempt, but they do so in slightly different ways. Depending on the context, one of these synonyms may be more appropriate than others, but all can be used to describe someone who is retaking a test or exam.