"신발" means all kind of shoes. "구두" used for dress shoes usually. as like high heels, business shoes.

구두 is a kind of 신발. 테니스 신발 or 운동화 is also a kind of 신발. We don't wear 구두 when we exercise. High heel is a kind of 구두 and I also wear 구두 made of leather. You know what 신발 and 구두 are. Never mind your language program.

Your right, 신발 is general word for shoes and footware. But if your taking about real real tennis shoes like the kind in tennis match they would be 테니스 신발. 구두 does mean high heels and dress shoes and if you want to distinguish gender you have 남성구두 for men and 여성구두 for women. 정당구두 is probaby common way to say dress shoes/ formal shoes for men. But I think 구두 in general refers to high heels. So general word for footware and shoes is 신발

"신발" means all kind of shoes. "구두" used for dress shoes usually. as like high heels, business shoes.

you might encounter another word for specialty shoes.. the hanja 화 would be all useful for that. e.g. 운동화, 경기화. I believe 화 is not to be used alone though. Just to complicate your life a little bit more.