What do you call the best pupil in a class in a single word? The pupil who has the best grades. I need this word NOT to be pejorative, like nerd, geek, teacher's pet, and so on.
The best match I can think of is the term "valedictorian." This word is only appropriate in the context of a graduating class, but it is the closet single word match I can think of.
According to Merriam-Webster the definition of valedictorian is:
valedictorian - noun - the student who has the highest grades in a graduating class and who gives a speech at graduation ceremonies