A small, short tail, especially on a rabbit.
A scut is a cute and small thing, like a rabbit's tail.
Examples:
The rabbit has a little scut.
The scut on the rabbit is white.
I saw a rabbit with a fluffy scut.
The scut on the rabbit looks like a puff.
The scut on the rabbit is the smallest thing I've ever seen!
The rabbit wiggles its scut when it hops.