If something is stubbier, it is shorter and thicker than something else.
Stubbier can make people think of things that are strong and a little bit cute.
Examples:
The baby elephant is stubbier than the grown-up one.
My dog is stubbier than your dog.
The stubbier pencil is easier to hold.
The stubbier tree is harder to climb.
The stubbier the better for some things.
The stubbier the carrot, the easier it is to eat.