Quick definitions from WordNet (substitutable)
▸ adjective: (of words) interchangeable in a given context without changing the import of the expression
▸ adjective: capable of being exchanged for another or for something else that is equivalent
▸ adjective: (of words) interchangeable in a given context without changing the import of the expression
▸ adjective: capable of being exchanged for another or for something else that is equivalent