It's kind of interesting question, because I've never thought of any link between the two as a native Korean. "~꾸러기" means a person who overdoes something. "~꾸러기" is often used when we call kids, whereas "꾼" is often used when we call someone who does things habitually or overly. "꾼" usually has a negative connotation. 장난꾸러기 : a mischievous boy 잠꾸러기 : a sleepyhead 말썽꾸러기 : a troublemaker 사기꾼 : a con man, crook 도박꾼 : a gambler (not ordinary people who sometimes enjoy gambling, usually a person addicted to gambling definitely for money)