ADJ [usually ADJ n]有自动保险装置的;具有自动防故障性能的 Something that is fail-safe is designed or made in such a way that nothing dangerous can happen if a part of it goes wrong. 有自动保险装置的;具有自动防故障性能的
The camera has a built-in failsafe device which prevents it from working if the right signals aren't received.