The term bet can be used in a few different ways on social media but generally means agreed or okay. For instance, someone might say, Want to grab lunch later? and the other person responds, Bet . It can also be used as a shorthand to mean you can count on it or trust me.
These are the most common slang terms, according to the parent survey, along with their Urban Dictionary defintion. Sus - "Giving the impression that something is questionable or dishonest; suspicious." Bet - "An expression that means 'I agree', 'good news'."
