It’s almost Halloween. “Boo!” is used to scare people, usually while wearing a scary costume. But did you know “boo” is also used in English to describe someone special to you?Read all about it here and practice your possessive adjectives!Sign up for free English practice and get your free guide to American slangGet our weekly newsletter and learn 30 slang words every English speaker should know! I will never give away, trade or sell your email address. You can unsubscribe at any time.