intending to be humorous rather than serious
facetious - playful
The word ‘facetious’ can be used in a positive or neutral way when you want to make it clear that something you said was intended to be playful or tongue-in-cheek rather than taken literally. However, it is most commonly used in a negative context to express disapproval at somebody joking inappropriately or not taking something as serious as they should be.
Don’t worry, I don’t really expect you to give me a prize for coming up with that idea. I was just being facetious!
I called this meeting to discuss a very serious matter, so I could do without your facetious remarks.
Jack’s facetiousness is down to immaturity and a lack of experience. He needs to learn how and when to use his humour more appropriately.
Mary didn’t make that comment to me facetiously. She said it sincerely in a deliberate attempt to cause offence.