Invalid
Invalid adjective - Chronically or repeatedly suffering from poor health.
Usage example: an old and now invalid woman who rarely gets out anymore
Weak is a synonym for invalid in feeling topic. In some cases you can use "Weak" instead an adjective "Invalid", when it comes to topics like sickly, false, disabled.
Mutual synonyms
Both words in one sentence
- Indeed monarchists often note that revolutions only happen against weak rulers (Charles I, Louis XVI, Nicholas II) rather than strong rulers, which means that The Kingdom as a system is not invalid except for the weak rulers who potentially come to power.
Source: Analysis / Democracy Is Flawed
Cite this Source
Weak and Invalid. (2016). Retrieved 2026, August 13, from https://thesaurus.plus/related/invalid/weak
Invalid & Weak. N.p., 2016. Web. 13 Aug. 2026. <https://thesaurus.plus/related/invalid/weak>.
Weak or Invalid. 2016. Accessed August 13, 2026. https://thesaurus.plus/related/invalid/weak.
Google Ngram Viewer shows how "invalid" and "weak" have occurred on timeline