invalid.

1. Having a conclusion that does not follow logically from the stated premises.

2. Failing the requirements for legal force, official recognition, or acceptable use.

3. A person seriously or chronically ill, especially one described as unable to lead an active life.

Use it for

Words that belong together

• invalid inference
• invalid argument

On the page

The inference is invalid because the conclusion does not follow.

Usage notes

Primary category: analysis / argumentation / evidence. Forms: Normally non-gradable; no ordinary comparative or superlative. Noun singular invalid; plural invalids. Legacy lexical fields mirror sense 1 only. Use numbered sense fields for all meanings. Established modern English lexical item. No separate regional spelling or grammatical inflection entry. Writing functions: evidence, inference, qualification. Commonness: common.