serious

adjectives

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!"
is derived from
antonym
is similar to
characterized by a firm and humorless belief in the validity of your opinions
"both sides were deeply in earnest, even passionate"; "an entirely sincere and cruel tyrant"; "a film with a solemn social message"
is similar to
dignified and somber in manner or character and committed to keeping promises
"a grave God-fearing man"; "a quiet sedate nature"; "as sober as a judge"; "a solemn promise"; "the judge was solemn as he pronounced sentence"
is similar to
excessively serious
is similar to
not to be taken lightly
"statistics demonstrate that poverty and unemployment are very real problems"; "to the man sleeping regularly in doorways homelessness is real"
is similar to
acting with or showing thought and good sense
"a sensible young man"
is similar to
tending to make sober or more serious
"the news had a sobering effect"
is similar to
of a substantial character and not frivolous or superficial
"work of solid scholarship"; "based on solid facts"
is an attribute of
the trait of being serious
"a lack of solemnity is not necessarily a lack of seriousness"- Robert Rice
of great consequence
"marriage is a serious matter"
is derived from
is similar to
of great significance or value
"important people"; "the important questions of the day"
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"; "a life-threatening disease"
is derived from
appealing to the mind
"good music"; "a serious book"
completely lacking in playfulness
is derived from
requiring effort or concentration; complex and not easy to answer or solve
"raised serious objections to the proposal"; "the plan has a serious flaw"
is similar to
not easy; requiring great physical or mental effort to accomplish or comprehend or endure
"a difficult task"; "nesting places on the cliffs are difficult of access"; "difficult times"; "why is it so hard for you to keep a secret?"