v. t. [ imp. & p. p. Deteriorated p. pr. & vb. n. Deteriorating ] [ 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. [ 1913 Webster ]
The art of war . . . was greatly deteriorated. Southey. [ 1913 Webster ]