Definition of "yackety-yak" 
- (noun) Slang Prolonged, sometimes senseless talk.
Use "yackety-yak" in a sentence
- "Whew, that was a lot of yackety-yak on my part ... but then, I have much to talk about after a long break."
- "They lapsed into a long pondering silence at the board, then started talking at once, yackety-yak together."
- "Left were the portly, graying bartender, a youngish, blonde waitress of hardbitten looks adding up her tabs, and a yackety-yak goodfella talking a blue streak at the end of the bar."