Definition of niggling for English Language Learners. : causing you to feel a slight pain or to be worried or annoyed for a long time.
What is PPAP? The Production Part Approval Process (PPAP) is a standardized process in the automotive and aerospace industries that helps manufacturers and suppliers communicate and approve production designs and processes before, during, and after manufacture.
Pen Pineapple Apple Pen (PPAP) by Piko-Taro. This may very well be the greatest thing on the internet right now. PPAP, which stands for Pen Pineapple Apple Pen, is an infectiously addictive song and dance created by singer-songwriter Piko-Taro.