be (as) green as a gooseberry
To be very young, immature, and/or inexperienced. Are you sure he's fit to run your campaign? He's just out of college and still as green as a gooseberry!
green as a gooseberry
Very young, immature, and/or inexperienced. Are you sure he's fit to run your campaign? He's just out of college and still as green as a gooseberry!