disimprovement

Noun

disimprovement (countable and uncountable, plural disimprovements)

1. Reduction from a better to a worse state.
   • [...] '[T]is very reaſonable, that all ſhould be obliged to the Law of Justice. [...] And as to the Public, 'twould be all one as if there were no Property; and then for want of Encouragement and Security, the final iſſue of the matter would be, an utter neglect and diſimprovement of the Earth, and...1687, John Norris, “The Christian Law Asserted and Vindicated, or A General Apology for the Christian Religion, both as to the Obligativeness and Reasonableness of the Institution”, in A Collection...
   • From day to day the intelligent student can watch the course of the affection before him, notice the finest shades of improvement or disimprovement, test the results of treatment, and verify for himself the truth of both diagnosis and prognosis.1884 November 1, H. M. J., “A Handbook of the Diseases of the Eye and Their Treatment. By Henry R[osborough] Swanzy, A.M., M.B., F.R.S.C.I; Surgeon to the National Eye and Ear Infirmary; Ophthalmic...

   Synonyms:

   decline, deterioration, worsening

   Antonyms:

   amelioration, betterment, improvement

2. (informal, rare, influenced by the German noun Verschlimmbesserung) Attempt to make something better while ending up worse than before.