Plain English Meaning
A severe mental illness where someone can't tell what's real from what isn't. The FAA does not allow pilots to fly with this condition unless they get a special exception.
Full Definition
A serious mental health condition in which a person loses contact with reality, typically involving hallucinations, delusions, or severely disorganized thinking. In FAA medical certification, psychosis is a disqualifying condition that prevents issuance of a medical certificate unless a special issuance authorization is granted.
Context Anchor
Seen in FAA medical certificate discussions, especially when reviewing mental health conditions that may affect a pilot’s ability to fly safely.
Derivation
From Greek 'psyche' meaning mind or soul, and '-osis' meaning a condition or abnormal . So 'psychosis' literally means a condition of the mind -- specifically one where mental functioning has down.