What kind of imitation of the disbelievers is prohibited by the Prophet, sallallaahu ‘alayhi wa sallam?

All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.

Muslims are generally prohibited from imitating the disbelievers, whether in appearance, their way of dressing, hairstyles, their ways of eating, or anything else that characterizes them. In other words, the Muslim is prohibited from doing whatever may make others think that he is one of them.

However, this does not include things that have become widespread among Muslims and which do not characterize the disbelievers, even if such things were originally taken from them. Al-Haafith Ibn Hajar mentioned that anything which used to be a distinguishing feature of the disbelievers but is no longer so is not disliked to be used by Muslims.   

And Allaah Knows best.