Apple knocker American informal noun slang
An ignorant or unsophisticated person who moved from the countryside to the city
I bet that apple-knocker will never be able to catch up with the city life.
A fruit picker
Look, man! I know nothing about it, I swear! I'm just an old apple-knocker.
Be ignorant, innocent or totally unaware; not know what's what
Uninformed or ignorant of something.
Not inteligent, and unable to understand difficult and complicated things or ideas
To be kept in the state of not having enough knowledge or information about something.
This phrase appeared between 1910 and 1915. It came from the practice of knocking apples from the trees to harvest them.