| substitute(adjective, reserve, extra, alternative, subsidiary) |
| alternate(reserve, extra, substitute, subsidiary, auxiliary) |
| alternative(adjective, extra, auxiliary, supernumerary, back-up) |
| commutable |
| counterfeit(adjective, extra, auxiliary, supernumerary) |
| ersatz(adjective, extra, auxiliary, supernumerary) |
| false(adjective, extra, auxiliary, supernumerary) |
| fungible |
| makeshift(extra, auxiliary, supernumerary) |
| mock(adjective, extra, auxiliary, supernumerary) |
| representative(adjective, extra, auxiliary, supernumerary) |
| secondary(adjective, reserve, subsidiary, supportive) |
| simulated(adjective, extra, auxiliary, supernumerary) |
| spurious(adjective, extra, auxiliary, supernumerary) |
| substitutional |
| substitutionary |
| vicarial(reserve, extra, substitute, subsidiary, auxiliary) |
| vicarious(adjective, extra, substitute, auxiliary, supernumerary) |
| acting(extra, auxiliary, supernumerary, back-up, flipside) |
| additional(extra, auxiliary, supernumerary) |