1. We need context. It could mean take a chance on something unknown, it could mean draw a conclusion based on little knowledge, or it could even be part of a rude dismissal (go away).
2. Do you know the word "cheeky"? If you are getting scolded or talking about something serious, and you make a remark that is silly, or questions that person's authority, or is intended to be funny but is the wrong time, you may be told not to "get flip."