D defs.my
Entry 4 senses Webster, 1913

Serious

/sĭr'-ē-əs/ · Se·ri·ous · IPA /ˈsɪɚ.i.əs/
01 a. Grave in manner or disposition; earnest; thoughtful; solemn; not light, gay, or volatile.
  1. 1.
    Grave in manner or disposition; earnest; thoughtful; solemn; not light, gay, or volatile.
    “He is always serious, yet there is about his manner a graceful ease.” Macaulay.
  2. 2.
    Really intending what is said; being in earnest; not jesting or deceiving.
  3. 3.
    Important; weighty; not trifling; grave.
    “The holy Scriptures bring to our ears the most serious things in the world.” Young.
  4. 4.
    Hence, giving rise to apprehension; attended with danger; as, a serious injury.