Is it permissible for a man to describe his wife with vulgar words such as "sharmouta" (whore/slut) or "qahba" (whore/prostitute), especially if the wife is not offended by that, and is the statement of Sheikh Ahmad Al-Haji Al-Kurdi that there is no sin in that correct?

Slander and verbal abuse are forbidden and contrary to the Muslim character, for the Prophet, peace and blessings be upon him, said: "The believer is not a slanderer, nor a CURSER, nor an obscenity utterer, nor a foul-mouthed person," and he also said: "Indeed, Allah detests the obscene, foul-mouthed person." The mentioned insults are not permissible for a Muslim to address his wife or anyone else with. Some scholars considered them to be slander that necessitates the prescribed punishment (حد), such as saying "O harlot" to one's wife or a non-mahram woman, which is the apparent view among the Shafi'is. The dropping of the prescribed punishment may occur due to the wife not demanding her right, but it is not permissible to allow these insults under the pretext that the wife is not offended.