An old phrase used to discribe a small child, but what exactly is a "nipper" and why do we call children this?
Well, back before child labor laws, small children were employed on large ships because they were small enough to fit down the hawse pipe that leads the chain out to the anchor. There was no way the crew on the ship could lift the anchor by hand, so they needed to use a capstand to provide the force needed. The issue is that the chain the ship used didn't fit on the capstand, so they used a rope for this purpose called a "nipper". Yes, a rope needed to be tied to the chain so that it could be hauled in with the capstand and that would take the weight off the chain so that the crew could haul the chain rode up onto the deck. This was called "nipping" and you needed someone small enough to crawl down the hawse pipe to tie the nipping line to the chain.
Naturally, a small child would fit through the pipe the best, and since they were tying the nipping line, they were naturally called "little nippers".
Next time you see a little one running around and call them a "little nipper", just imagine them climbing down the chain as close to the sea as possible to tie a nipping line to it!