An antonym for diagnosis is ‘misdiagnosis.’
Explanation: The term ‘diagnosis’ refers to the identification of a disease or problem based on the signs and symptoms presented. In contrast, ‘misdiagnosis’ indicates an incorrect or false assessment of a condition, thus serving as an opposite in meaning. While diagnosis aims for accuracy in identifying a health issue, a misdiagnosis results in errors that can lead to inappropriate treatments or misunderstandings regarding a person’s health status.