deterioration

noun

Etymology: Borrowed from French détérioration; morphologically deteriorate + -ion.

1. The process of making or growing worse, or the state of having grown worse.

   “From 1945 onwards, deterioration in the condition of the brickwork in the arch soffits was kept under close observation, and in 1951 it was decided that strengthening must be undertaken.”

   “The Queen may be celebrating her jubilee but the Queen's English Society, which has railed against the misuse and deterioration of the English language, is to fold.”