You are not to use such words jestingly. Since you spoke them thoughtlessly in a joking way, it cannot be ruled as Zhihar. We are to pray to Allah ‘not to take us to task if we forget or make a mistake.’

 

The Prophet, peace be upon him, said, “Allah has excused my Ummah of their thoughtless mistakes or forgetfulness or actions that they do under coercion.” (Ibn Hibban)

 

Having said this, however, I would urge you to seek repentance of Allah and resolve never to do the same and also encourage you to give some charity to expiate for your mistake.

 

Almighty Allah knows best.