For example, someone might be called "Corky" because they are:
* Cork-like: Maybe they are a bit bouncy, lighthearted, and full of energy, like a cork on water.
* Cork-haired: Perhaps they have curly or wavy hair, reminiscent of cork.
* Cork-headed: This could be a playful jab at someone who is a bit dense or slow to understand.
Without more context, it's difficult to say for sure what "Corky" is short for.