What is the correct preposition for synonym? for or of?
Or both of them?
Synonym is "another word for", so the word "synonym" takes "for".
(e.g. pretty is a synonym for beautiful)
NOT A TEACHER
(1) Great question.
(2) According to most dictionaries, both are "correct" when you mean that a word has
the same meaning as another word:
"Small" is a synonym of/for "little."
(3) BUT -- as the Learner's Dictionary (on the Web) says -- there is one time when you
must use "for."
(a) When a word suggests a particular idea or quality:
(i) He is a tyrant whose name has been a synonym for oppression.