definition of
serious

[1] #1 serious a. 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!". wn

[2] #2 serious s. of great consequence; "marriage is a serious matter". wn

[3] #3 serious s. [dangerous, grave, grievous, severe, life-threatening] 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". wn

[4] #4 serious s. [good] appealing to the mind; "good music"; "a serious book". wn

[5] #5 serious a. [unplayful, sober] completely lacking in playfulness. wn