The word stubby (English) means "short and thick". It is often given as a nickname to (mostly male) people of short stature, or in this case, to someone with short and thick fingers.... (Wikipedia).
Lamont is a Scottish surname, in use since medieval times, and comes from the Old Norse name Logmathr (log meaning "law" and mathr (mann) meaning "man") (Internet Surname Database).
Lexicon timeline of Quidditch
From the Web
Writing by J.K. Rowling on Pottermore: History of the Quidditch World Cup
Harry Potter Wiki: Lamont