Since its a sibling, and siblings tend to be in a person's close circle of people, informal speech is used.
A fitness award was won by my best friend
B, A person who is obsessed with themselves
Crybaby, Pacify her, show and tell, k-12, teachers pet , mad hatter , mrs, potato head that’s all i can name for now i was a big fan of hers a long time ago lmshsjd
It belongs in the stimulant category