Invalid and Irrational

Invalid

Invalid adjective - Not using or following good reasoning.
Usage example: an argument which has one untrue premise is invalid

Irrational is a synonym for invalid in illogical topic. In some cases you can use "Irrational" instead an adjective "Invalid", when it comes to topics like worthless, unfounded.

Irrational

Irrational adjective - Not using or following good reasoning.
Usage example: it's irrational to think that you can continue to consume an excess of calories and not gain weight

Invalid is a synonym for irrational in illogical topic. You can use "Invalid" instead an adjective "Irrational".

Nearby Words: irrationality, irrationally
Cite this Source
Irrational and Invalid. (2016). Retrieved 2026, August 15, from https://thesaurus.plus/related/invalid/irrational
Invalid & Irrational. N.p., 2016. Web. 15 Aug. 2026. <https://thesaurus.plus/related/invalid/irrational>.
Irrational or Invalid. 2016. Accessed August 15, 2026. https://thesaurus.plus/related/invalid/irrational.
Google Ngram Viewer shows how "invalid" and "irrational" have occurred on timeline