an abreviation of the word signature. more specifially a basketball players signature shot. the actual shot called "siggy" originated from my friend Travis who would shoot a granny shot extremley high and over time it went from being called his signature to simply his "siggy". to shoot a siggy first u must cock the ball between your legs and then launch it into the air currents (as high or higher than the backboard). lastly as you release the ball you must yell the word "siggy" in a high pitched annoying voice (much like the sound a dog makes when it is kicked in the stomach)
Trav, stop shooting siggys! your gonna hit my gutters!