Having more snags or sharp points that stick out.
Snaggier things might be more dangerous or harder to move around.
Examples:
The snaggier branch is harder to climb.
Her hair is snaggier than mine.
The snaggier path is more difficult to walk on.
I don't want to play in the snaggier bushes!
The snaggier the fence, the harder it is to climb.
The snaggier the dragon's teeth, the scarier it is.