Of no force, weight, or cogency; not valid; weak.
When applied to a measurement scale, a lack of validity means that the numbers assigned do not reflect the true magnitude of the property being measured. (Pronounced with the second syllable accented, to distinguish this adjective from the homographic noun designating a person in poor health.)
an argument is deductively invalid when it is possible for its conclusion to be false when the premises are true.
having no cogency or legal force; "invalid reasoning"; "an invalid driver's license"
no longer valid; "the license is invalid"
A deductive argument that is not logically successful. An argument is invalid if and only if it is possible for an argument with such a form to have all true premises and a false conclusion.
an argument that is not valid. We can test for invalidity by assuming that all the premises are true and seeing whether it is still possible for the conclusion to be false. If this is possible, the argument is invalid.
A marriage is not valid, and so is not a Sacramental marriage
indicates a condition which is not valid within a given context.
Not valid (q.v.).
A name that is not acceptable (valid) under the codes
A name or nomenclatural act that is not valid under the Code.
A marriage which was not divinely ratified, and so was no marriage
An approach or example that is flawed and does not lead to the correct solution of the problem. An invalid approach would be to simplify the expression from left to right, disregarding the order of operations. A valid approach would be to simplify the expression using the order of operations.