someone who holds a negative value to human birth. usually for environmental reasons (overpopulation), or because life sucks and they don't want to put someone else through it
tim: do you ever wanna have children?
sarah: not of my own, i'm an antinatalist. i am open to adoption though!
After he studied his state representative's beliefs he decided to become an antiestablishmentarianist. My folks aren't happy that I am an antiestablishmentarianist.