1. substitutable - Noun
2. substitutable - Adjective
3. substitutable - Adjective Satellite
capable of being exchanged for another or for something else that is equivalent
(of words) interchangeable in a given context without changing the import of the expression
Source: WordNetHuman capital is substitutable, but not transferable like land, labor, or fixed capital. Source: Internet
The pronoun is described there as "a part of speech substitutable for a noun and marked for a person." Source: Internet