A small worthless prick, or a woman who had a sex change and became a poor example of a male. Could also be used to describe a non functioning penis, especially a small one. Many times in history, a Welshans has been used to replace a worn out clitoris on a dog.
1. Ken is such a Welshans, he looks like a dog clitoris.
2. Ken used to be Kendra. What a little prick.
3. Find me a Welshans, my doberman needs a new clitoris.