fallback       
adjective [ before noun ] uk/ˈfɔːl.bæk/ us/ˈfɑːl.bæk/
 (计划等)应变的,退一步的
A fallback plan or position can be used if other plans do not succeed or other things are not available.
  Do we have a fallback position for these negotiations? 这些谈判我们有应变方案吗?