is there an other word for synonym?

Answer 1

try one of these: equivalent, substitute

Some folks will claim that "synonym", ironically, HAS no synonyms. But that is based on a misunderstanding of what a synonym actually is. To be a synonym, a word does NOT have to have exactly the same meaning in all instances. It simply has to be able to convey the same meaning in SOME cases. If you say "I can't think of a synonym for 'obnoxious'." you could use "a substitute" or "an equivalent" in place of "a synonym" and it would convey the same sense. Thus, in this case, these words function as synonyms for "synonym"

(Note: In case someone suggest "similar" or "same", these don't quite work. They are synonyms for the adjective "synonymous", not the noun "synonym")

http://www.thefreedictionary.com/synonym

Answer 2

Not technically.

But words like "interchangeability" and "parity" are close.

Interchangeability: Capable of being put or used in the place of each other.

Parity: Equivalence; correspondence; similarity; analogy.

Be creative!

Answer 3

dictionary.com.