A spoonie is someone living with a chronic illness.
It mostly refers to physical chronic illnesses, though it has been known to be a helpful term for those with chronic mental illness as well.
It originates from Christine Miserandino's Spoon Theory story, in which she explains
what it's like to live with chronic illness to a friend, and uses a handful of
spoons to demonstrate.
For example, daily activities that healthy people tend not to think about take tolls on people with chronic illness. You start the day with a certain number of spoons, and play your day around not running out.
Socializing might cost spoons, using the stairs might cost spoons, lifting things might cost spoons, etc.