When something is bound to work out, you can call it foolproof. Your foolproof plan for having a great summer might involve spending lots of time at the beach.

If your dog tends to wander and can also jump six feet in the air, a foolproof plan for keeping her in your yard might involve an eight foot fence. You can also use foolproof as a verb: "I'm going to foolproof the instructions for heating up your dinner, so that no one sets the stove on fire this time." Foolproof is an early twentieth century American English word that combines fool, or "silly person" and proof, "resistant."

Definitions of foolproof
  1. adjective
    not liable to failure
    “a foolproof identification system”
    synonyms: unfailing
    incapable of failure or error
  2. verb
    proof against human misuse or error
    foolproof this appliance”
    synonyms: goof-proof, goofproof
    see moresee less
    type of:
    make resistant (to harm)
Word Family