antigram
/ˈæntɪˌɡræm/
noun
- A word or phrase formed by rearranging the letters of another word or phrase, where the new arrangement has an opposite or contrasting meaning.
- "Silent" is an antigram of "listen" because one means quiet and the other means to hear.
- She found an antigram for "funeral" — "real fun" — which turns a sad word into a happy phrase.
- Creating an antigram is harder than a simple anagram because the meanings must oppose each other.