All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
Dancing during the feasts and lawful ceremonies is lawful if it doesn't lead to neglecting any obligations (religious or not) and doesn't go beyond moderation. It should not also be accompanied by forbidden matters like music, drinking alcohol, mixing with the opposite sex or taking off one's obligatory garments, and the like. It is narrated by Al-Bukhari and Muslim that the Prophet Muhammad once stood in front of ‘Aa’ishah to cover her while she was watching some Ahbash (Ethiopians) playing with their swords. In some other words of this Hadeeth, it is said that they were dancing and that it was on a feast day. On the other hand, dancing is not a profession of a decent person.
For this, the jurists have rejected the testimony of the person who is known to dance a lot.
Allah knows best.