serious (
http://definr.com/serious)
adj 1: concerned with work or important matters rather than play or
trivialities; "a serious student of history"; "a
serious attempt to learn to ski"; "gave me a serious
look"; "a serious young man"; "are you serious or
joking?"; "Don't be so serious!" [ant:
frivolous]
2: of great consequence; "marriage is a serious matter"
3: causing fear or anxiety by threatening great harm; "a
dangerous operation"; "a grave situation"; "a grave
illness"; "grievous bodily harm"; "a serious wound"; "a
serious turn of events"; "a severe case of pneumonia"
[syn:
dangerous,
grave,
grievous,
severe]
4: appealing to the mind; "good music"; "a serious book" [syn:
good]
5: completely lacking in playfulness [syn:
unplayful,
sober]
[ant:
playful]
6: requiring effort or concentration; complex and not easy to
answer or solve; "raised serious objections to the
proposal"; "the plan has a serious flaw"