the stride made by a man
奞 centers on a person's stride or step, specifically the length or manner of a stride made by a man. The meaning is narrow and concrete, with no clear abstract extensions.
奞 combines 大 (big, person) on top with 隹 (bird) below. The exact historical development is uncertain, but it may depict a person striding like a bird or a large bird's stride.
A big 大 bird 隹 takes a long stride: 奞 is the stride made by a man.
For シュン, imagine a man striding so fast he makes a 'shun' sound as he passes by: shun -> シュン.