slang An honest, respectable, and law-abiding man. Used primarily in criminal and prison communities. The key is to find some square john to take the fall for you when the feds finally catch on to the scheme. I know you can't understand how I can sleep at night doing what I do. But see, I look at a square john like you, a slave to your work and your mortgage, and I think you're the crazy one.
See square john
square johnand square apple
n. someone who obeys the rules; a square. Fred is a square john. There’s no point in worrying about him. I look like a square john, but I’m really quite a devil.