marry, arrange a marriage
娶 centers on taking a wife: marrying a woman or arranging a marriage, with the focus on the act of bringing a bride into the family.
娶 combines 取 (take) and 女 (woman), expressing the idea of taking a woman as a wife. The component 取 likely also contributes the sound.
The top part 取 means 'take', and the bottom part 女 means 'woman'. Picture a man taking a woman as his bride: 娶 is to marry.
For シュ, imagine a groom taking his new wife's shoe off at the wedding: shoe -> シュ, and he takes her as his bride.