Remus Lupin was also known as “Moony” to his friends because he transformed into a werewolf during the full moon. harrypotter.wikia.com

Remus Lupin as a werewolf. harrypotter.wikia.com

J.K. Rowling uses lots of charactonyms throughout the Harry Potter series. Merriam Webster defines charactonym as “a name  for a fictional character  that suggests a distinctive trait of the character.”  In Harry Potter and the Prisoner of Azkaban, a new Defense Against the Dark Arts teacher is hired and his name is Remus Lupin. Lupin is very similar to the word lupine,  an adjective which means of or relating to a wolf.  Lupine comes from the Latin word lupus meaning wolf.  Lupin’s name betrays what he actually is, a werewolf! I like trying to decipher the charactonyms that J.K. Rowling uses in her books, because it makes the books more interesting and exciting.