Was heißt »Ulk« auf Englisch?

Das Substantiv Ulk lässt sich wie folgt von Deutsch auf Englisch übersetzen:

Synonyme

Ernst:: austerity; earnestness; seriousness
Humorlosigkeit:: humorlessness; humourlessness; lack of humor; lack of humour

I suppose it's just a joke.
Jack laughed at Christina's joke; the others all just shook their heads blankly.
I suppose it was a joke.
You didn't get the joke.
"I thought Tom's joke was really funny." "I didn't, and I don't think Mary did, either."
The whole class began to laugh at his joke.
The joke appeared not to go down well with Sarkozy.
Hundreds of motorists stopped in the middle of the road to look at a supposed UFO. It was Tom flying by in a saucer-shaped hot-air balloon to play an April Fool's joke.
The pay here is a joke.
I wish it were all a joke.
That's nothing to joke about.
Unfortunately it's not a joke, but the sad reality.
Tell me a typical Japanese joke.
Tom's joke was hilarious.
The joke Tom told was hilarious.
That was definitely a joke.
The whole class burst out laughing at Tom's joke.
It was supposed to be a joke.
It was intended as a joke.
It was meant to be a joke.