The remark was made half in jest.

这话是半开玩笑说出的。

《牛津词典》

"Be useful, and do me a service, "said he, in jest.

他开玩笑地说：“做个有用的人，并帮我个忙。”

youdao

Do not say that even in jest!

不要说这种话，哪怕是开玩笑，也不要说这种话！

youdao

So you know I say half in jest but it's actually really sad.

这话虽然是半开玩笑，但其实很可悲。

哈佛公开课 - 幸福课课程节选

Almost in jest you invoke the devil, and to your horror the devil appears.

WSJ: Joseph Calleja | Faust | Here to Deal With the Devil | Cultural Conversation by Barrymore Laurence Scherer

Terms like "bipolar", "autistic" and "schizophrenic" are often used in jest to describe character traits.

BBC: Magazine

Roger Ailes suggested, perhaps less than half in jest, that Petraeus run for President.

NEWYORKER: General Principles