foolproof
fool-proof
adjective
So simple and effective that it cannot fail or be misused by anyone.
"The new instructions are completely foolproof."
Thesaurus
Synonyms: infallible, unfailing, goofproof, goof-proof
fool-proof
So simple and effective that it cannot fail or be misused by anyone.
"The new instructions are completely foolproof."
Synonyms: infallible, unfailing, goofproof, goof-proof