Mid 50's to mid-60's beatnik/hipster slang.
Somewhat equivalent to today's "dude" or "man" but with a much cooler zen-bohemian and/or streetwise hipster attitude.

when you're hungover as shit after a spending a night drunk as a skunk

The bestest of the dads. They buy you honey but cheerios. Not plain cheerios. He is King Kong.

Slang for dad, or father.

(noun) slang for an older man that you do not respect
(adj) synonmous w/ cool, killer, boss, groovy, etc.

Daddy-o is a finger game. You make an OK sign with your pointer finger and thumb, then show it below the waste. If someone looks at it, you have to make an "X" on their upper arm, hit it lightly, then wipe it off. If you forget the steps, they have the right to do it to you and hit you hard. If someone spears your Daddy-o, you are lame and deserve to be hit hard. It is a fun game and contagious, especially if it starts being played in a school.