Bob Cousy's parents arrived in New York from Alsace France in September 1928. He was born a month later. He grew up speaking French as his first language, but also learned English. He had a speech impediment causing him to pronounce his r's like l's. So his friends started calling him flenchy instead of frenchy.
He was also called Cous (Cooz), a phonetic play on his last name. Kind of like John Bagly is called bags. Cousy is pronounced coozy, not cowsy. This nickname had nothing to due with the crude American slang that originated in the 1950s at the earliest.
He was later dubbed the Houdini of the hardwood because the basketball floor is called the hardwood and he had magical ball skills. Harry Houdini was a famous magician. Although, actually, I think Houdini was better known for being an escape artist than for slight of hand.
If I recall correctly, the 93 year old Bob Cousy is the oldest living former NBA player.