What does disimprove mean?
"Disimprove" is a verb meaning to become worse, or to make something worse — in effect, the direct opposite of "improve." Formed by attaching the negative prefix "dis-" to "improve," it follows a long English tradition of creating counterwords by negation. Although its meaning is transparent and instantly grasped, the word occupies a curious marginal position in English: major dictionaries have recorded it since at least the seventeenth century, yet it never achieved widespread currency and today survives chiefly in Irish and Scottish English, where speakers use it naturally for declining health, weather, property, or circumstances. In most other varieties, "worsen," "deteriorate," or "go downhill" are preferred. Its derivative noun, "disimprovement," is rarer still. For learners and writers, "disimprove" is best understood as a legitimate but regionally flavored alternative — useful for variety or local color, but likely to sound unusual outside Ireland, Scotland, and their diaspora communities.
verbTo become worse or to cause something to become worse; the opposite of improve.
- To become worse in condition, quality, or value.
- To cause something to become worse.
"The damp weather caused his cough to disimprove over the winter months."
"Her eyesight began to disimprove after years of working in dim light."
"Critics argued that the renovations would only disimprove the historic building."
It's a real word that means exactly what it looks like it should — the opposite of improve — yet most dictionaries treat it as a rarity, surviving mainly in Irish and Scottish English.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of disimprove
The word combines the prefix "dis-", from Latin indicating reversal or negation, with "improve", which itself derives ultimately from Anglo-Norman "emprouwer", meaning to turn to profit or advantage. "Improve" entered English in the late Middle Ages, and "disimprove" was formed on it as a straightforward antonym, appearing in written English from around the early modern period. It shares this root with words such as "approve" and "reprove", all tracing back through Old French to the Latin verb "probare", meaning to test or judge good.
Related word forms
How disimprove is actually used
Register is informal to neutral, and the word is markedly more common in Irish and Scottish English than elsewhere; speakers of standard American or southern British English typically prefer 'worsen' or 'deteriorate'. It carries no strong connotation beyond simple decline.
Easily confused with disimprove
"Impoverish" means to make poor, while "disimprove" means simply to make worse in quality or condition.