This is a very serious accusation.
He was involved in a serious collision.
She wasn't very serious.
I shot him a serious glare from across the room.
You are a serious contender for the Dumbest Question Ever Award.
Habitual lying is a serious weakness in a person's character.
John is a very serious man This is a very serious matter
most serious performers prefer constructive criticism to servile flattery.
The teacher was being serious when she was yelling at the student about being peremptory towards her.
"thoughtful not joking" is not a sentence and it does not contain the word "serious". Serious is an adjective, a word that describes a noun. Example: Justin has a serious expression on his face. The adjective "serious" describes the noun "expression".
The look on her face was very serious.The injuries are very serious.If you don't take your school work serious no good will come to you in life.I'm serious I didn't do it!
Some medicines have serious aftereffects.We may do wrong, but be ready to face the aftereffect.
"this play i serious so act like you care"
There are many people who are serious about school, while others are not.
Serious answer: Wait as the car draws near. Non-serious answer: This sentence will end with the word 'near'!
He's so jocular that you can't get any serious sentence from him.