Satou’s dog is very obedient.
What's with that guy? He is just a quiet nerd at school.
He’s an obedient kid.
Remember how you learned that 大人 means "adult?" Well this is the adjective version of that. The I-adjective (see how it ends in い?). What adjective do adults want to be able to use for their own kids? They want to say they are obedient, quiet kids!
You already learned this reading when you learned 大人! You should be able to read this too!