is 'Geez' used a lot? and when it is used?

Native speaker’s answer
Rebecca
I'd say it's fairly common! "Geez" is also sometimes spelt as "jeez," and is an abbreviation for "Jesus." It's an informal expression to indicate annoyance or surprise and a little more mild to use than "Jesus". So you can use it when you're annoyed by something or someone, and you can use it when you get surprised by something! Ex: Oh, geez! I didn't see you behind the door. You scared me! Ex: Jeez. Not her again. She's so annoying.