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