Open English Wordnet
Adjectives
(a)seriousconcerned 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!” (s)seriousof great consequence“marriage is a serious matter” (s)dangerous, grave, grievous, serious, severe, life-threateningcausing 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”,
“a life-threatening disease” (s)good, seriousappealing to the mind“good music”,
“a serious book” (s)seriousrequiring effort or concentration; complex and not easy to answer or solve“raised serious objections to the proposal”,
“the plan has a serious flaw”