Here are some words that come close, depending on the context:
* Equivalent: This emphasizes the same meaning.
* Paraphrase: This implies rewording while retaining the meaning.
* Analogue: This implies a similarity in function or effect.
* Counterpart: This implies a matching element in a different system.
* Equivalent word: This is a more literal phrase, but it emphasizes the word aspect of a synonym.
Ultimately, the best choice depends on the specific situation and what nuance you want to convey.