(as) green as grass British phrase
To be inexperienced with something and possibly naive.
I know Jane is as green as grass, but I'm sure she'll be able to do the job in just a matter of time.
You're still as green as grass. Next time try to ask someone for help, okay?
Extremely green.
That undercooked chicken made me become green as grass and have to vomit.
1. Being faultless or guiltless
2. Being naive or inexperienced
Be young or childish and not have had much experience
Not inteligent, and unable to understand difficult and complicated things or ideas