se⋅ri⋅ous /ˈsɪəriəs/ Show Spelled Pronunciation [seer-ee-uhs] Show IPA
–adjective 1. of, showing, or characterized by deep thought.
2. of grave or somber disposition, character, or manner: a serious occasion; a serious man.
3. being in earnest; sincere; not trifling: His interest was serious.
4. requiring thought, concentration, or application: serious reading; a serious task.
5. weighty or important: a serious book; Marriage is a serious matter.
6. giving cause for apprehension; critical: The plan has one serious flaw.
Synonyms:
2. sober, sedate, staid. 3. See earnest 1 . 5. momentous, grave.
Antonyms:
3, 5. trivial. MAD MATT
(
http://dictionary.reference.com/browse/serious)