Which assembly is unlawful in Nigeria?

It is simple. Rather than listing Secret Society among others. Let us put it this way. Any assembly you know that want to carry out a purpose or carry themselves in a manner that will bring panic or cause the neighborhood to fear in order to disturb the peace , they are unlawful assembly.

Moreover, section 88 of criminal code make it unlawful to “ assemble together and bear, wear or carry arms, or exhibit symbol, emblem, banner, or flag calculated to promote animosity between persons of different religious faith or be accompanied by music, instrument otherwise calculated to promote such, and then join any parade or procession and then assemble to celebrate an event connected with any religious or other distinction between Nigerians, or of demonstrating any such difference are guilty of the offence”.