Failsafe is a term that is used to describe a system or device that is designed to prevent failure in the event of a malfunction. There are many words that can be used as synonyms for failsafe, such as foolproof, fail-proof, infallible, reliable, and safe. Each of these words carries a similar connotation of being secure and trustworthy. Other related terms include resilient, robust, dependable, and strong. When it comes to technology, some additional synonyms for failsafe might include backup, redundancy, and failover. Ultimately, all of these words convey a sense of assurance that something will work as intended and provide reliable results.