- (transitive) To make worse; to make inferior in quality or value; to impair.
- to deteriorate the mind
- The art of war, like every other art, ecclesiastical architecture alone excepted, was greatly deteriorated during those years of general degradation […]
- (intransitive) To grow worse; to be impaired in quality; to degenerate.
2011 January 8, Paul Fletcher, “Stevenage 3 - 1 Newcastle”, in BBC:
- It was turning into an abysmal afternoon for Newcastle and it deteriorated further when Tiote saw red for his challenge on Jon Ashton.
- (informal) slang: to nerf (used in gaming) something which is overpowered .