Invalid and Proper
Opposite meaning words
Invalid
Invalid adjective - Not being in agreement with what is true.
Usage example: that's an invalid assumption on your part
Proper
Proper adjective - Following the established traditions of refined society and good taste.
Cite this Source
Proper and Invalid. (2016). Retrieved 2026, July 22, from https://thesaurus.plus/related/invalid/proper
Invalid & Proper. N.p., 2016. Web. 22 Jul. 2026. <https://thesaurus.plus/related/invalid/proper>.
Proper or Invalid. 2016. Accessed July 22, 2026. https://thesaurus.plus/related/invalid/proper.
Google Ngram Viewer shows how "invalid" and "proper" have occurred on timeline