Yapping means making a lot of quick, high-pitched sounds, like a small dog barking.
Yapping can be annoying or noisy, like when a small dog won't stop barking.
Examples:
The little dog is yapping at the mailman.
Stop yapping, I'm trying to concentrate.
The birds are yapping loudly in the trees.
The yapping dog woke up the whole neighborhood.
The yapping was so loud, I couldn't hear anything else.
The little dog won't stop yapping at the cat!