Sirwilliam is a distinctive boys' name in United States, ranking #13925 in 2012 with 5 recorded births. This places Sirwilliam in the bottom 2% of ranked US boys' names for the year. Its actual usage is classified as Rare. The name reached its all-time peak in 2010 with 10 births ranking #8046. In 2012, approximately 1 in every 379,325 boys born was named Sirwilliam. RISING Recent data shows the name is currently rising.