/dɪˈtɪriəreɪt/
de·teri·or·ate
BrE /dɪˈtɪəriəreɪt/
NAmE /dɪˈtɪriəreɪt/
[I]
to become worse
Her health deteriorated rapidly, and she died shortly afterwards.
deteriorating weather conditions
~ into sth
The discussion quickly deteriorated into an angry argument.
de·teri·or·ation
BrE /dɪˌtɪəriəˈreɪʃn/
NAmE /dɪˌtɪriəˈreɪʃn/
[U, C]
a serious deterioration in relations between the two countries