Noun
sick note (plural sick notes)
(UK) A note from a doctor certifying the patient is ill, and therefore unable to go to work, school, etc.
Synonyms: (US) doctor's note, (US) excuse
Near-synonym: aegrotat
You know, I used to warm the thermometer on the light bulb... I was really good at being sick. I could forge my mother's signature on a sick note so well I was hardly ever at school. Graydon Carter