Is taunts by epithets considered an act of disbelief (takfīrī)?

"At-tanabuz" is the act of describing or calling a person by a characteristic or nickname that they dislike, or that contains dispraise, degradation, or mockery. This is forbidden, based on the Almighty’s saying: "And do not call each other by [offensive] nicknames." Among the forbidden nicknames is calling someone by a term that implies disbelief (kufr). Some have interpreted "at-tanabuz" as calling a person a disbeliever after they have embraced Islam. The Sharia has warned against declaring someone a disbeliever (takfir), for the Prophet, peace and blessings be upon him, said: "Any man who says to his brother: 'O disbeliever,' then one of them has surely fallen into it." The term "disbelief" in this Hadith is interpreted as minor disbelief, because accusing a believer of disbelief is like killing him, and killing is not disbelief.