Improve / Worsen / Deteriorate / Regress / Deprove
UsageImprove means become or make better. Use worsen for the general opposite, deteriorate for progressive decline, and regress for a return to an earlier or worse state. Do not use deprove as the opposite of improve in formal workplace writing.
Improve
Use when
Something becomes better or someone makes it better.
Example
“The revised workflow improved the user experience.”
Worsen
Use when
Something becomes worse or someone makes it worse.
Example
“The additional approval step worsened the user experience.”
Deteriorate
Use when
A condition, quality or performance becomes progressively worse.
Example
“Service reliability deteriorated after the migration.”
Regress
Use when
Something returns to an earlier, less advanced or worse state.
Example
“The process regressed to manual handling after the integration failed.”
Deprove
Use when
Avoid this form when you mean become or make worse; choose worsen, deteriorate or regress according to the intended meaning.
Example
“Replace 'The change deproved service quality' with 'The change worsened service quality'.”
Quick check
deprove, deproved, deteriorate used transitively where worsen is clearer, regress used for any decline without a return to an earlier state
Usage note
Rare or specialised uses of deprove may be found elsewhere, but it is not the standard opposite of improve in formal workplace English.