deteriorate
v.v. to become worse in quality or condition over time. You use this when something like your health, the weather, or a building is getting weaker or uglier.
v. to become progressively worse in quality, value, or character. Intransitive — describes a process of decline without requiring a direct object.
The old house began to deteriorate after years of neglect.
The patient's condition started to deteriorate rapidly overnight, requiring immediate medical intervention.
Despite several attempts at diplomatic mediation, relations between the two neighboring countries continued to deteriorate until all formal communication ceased.
Learned borrowing from Late Latin dēteriorātus, perfect passive participle of Late Latin dēteriorō (see -ate (verb-forming suffix)), further from Latin dēterior (“worse”). Cognate with French détériorer.
The verb is intransitive and does not take a direct object.