Other forms: deteriorated, deteriorating, deteriorates
To deteriorate is to grow steadily worse over time. Conditions deteriorated, deteriorating health, the weather deteriorated.
The steadiness is the point: deteriorating is a process rather than an event, which is why it suits health, buildings and relations. In medicine, a patient who is deteriorating needs escalation, and recognising it early is what early warning scores exist for. Note deterioration; and that the Latin deterior simply means worse.
1verbdeteriorateTo grow steadily worse over time.
“Her eyesight deteriorated as she got older, and she had to stop driving.”
deteriorate is a worsening.
Also accepted in games: worsen
Latin deteriorare comes from deterior, worse, which is a comparative with no positive form — there is no Latin word it is worse than.
Latin
dēteriorātus
English, today
deteriorate
Latin dēteriorātus, perfect passive participle of Latin dēteriorō (see -ate), further from Latin dēterior (“worse”). Cognate with French détériorer.
Etymology from Wiktionary, CC BY-SA