Invalid
Invalid adjective - Chronically or repeatedly suffering from poor health.
Usage example: an old and now invalid woman who rarely gets out anymore
Unsound is a synonym for invalid in false topic. In some cases you can use "Unsound" instead an adjective "Invalid", when it comes to topics like property, correct, worthless, unfounded. popular alternative
Unsound
Unsound adjective - Not being in agreement with what is true.
Usage example: an unsound and pernicious stereotype
Invalid is a synonym for unsound in property topic. You can use "Invalid" instead the word "Unsound" as an adjective or a noun, if it concerns topics such as correct, false, flimsy. popular alternative
Mutual synonyms
Both words in one sentence
- The premises and conclusion can be "true" or "false"; the chain of reasoning itself can be "valid" or "invalid"; the argument as a whole is either "sound" or "unsound".
Source: Sound, Valid, True
Cite this Source
Unsound and Invalid. (2016). Retrieved 2026, August 16, from https://thesaurus.plus/related/invalid/unsound
Invalid & Unsound. N.p., 2016. Web. 16 Aug. 2026. <https://thesaurus.plus/related/invalid/unsound>.
Unsound or Invalid. 2016. Accessed August 16, 2026. https://thesaurus.plus/related/invalid/unsound.
Google Ngram Viewer shows how "invalid" and "unsound" have occurred on timeline