The Brief: Boo'd up or booed up means to be in a romantic relationship.

DEEP DIVE
Boo’d up, a synonym for cuff or ship refers to when two people get together romantically.
all my friends be some type of boo’d up and i really just be in my room chillin like pic.twitter.com/vhq5YyhvCV
— aisha ♡ (@__AdoreAisha) September 26, 2018
i wonder how many couples caption for halloween will be 'BOO'd up'
— DJ Pendeja (@kattttttttt) September 26, 2018
It’s boo’d up szn and I’m single 😒
— Eva🇵🇹🍯 (@Evaaeuro) September 22, 2018
A song called Boo’d Up by Ella Mai is a song about being in love and boo’d up.