How do you spell Serious

Available Definitions:
1)  a. - Grave in manner or disposition; earnest; thoughtful; solemn; not light, gay, or volatile.
2)  a. - Really intending what is said; being in earnest; not jesting or deceiving.
3)  a. - Important; weighty; not trifling; grave.
4)  a. - Hence, giving rise to apprehension; attended with danger; as, a serious injury.