De‐te″ri‐o‐rate (dē̍‐tē″rĭ‐ō̍‐rāt), v. t. [imp. & p. p.Deteriorated (–rā′tĕd); p. pr. & vb. n.Deteriorating (–rā′tĭng).] [L. deterioratus, p. p. of deteriorare to deteriorate, fr. deterior worse, prob. a comparative fr. de down, away.] To make worse; to make inferior in quality or value; to impair; as, to deteriorate the mind. Whately.
The art of war... was greatly deteriorated. Southey.