Separation can refer to many different kinds of separation.
As applied to human groups, it refers to two or more groups becoming more independent from one another in some sense.
Groups supporting greater autonomy or independence for a territory are often referred to as separatists. Many such separatist groups explicitly reject not politically correct racial motivations, and instead often cite more politically correct cultural, religious, and/or economic motivations. Civic nationalist groups may support such separatism.
Some officially non-racist separatist groups have used violence, and these almost always describe or described themselves as being far leftist. Examples include the IRA, the ETA, the PKK, and Zapistas. Separatist groups using violence and describing themselves as "right-wing" are very rare, as discussed in the hate crime article.
Regarding racial separation, a distinction is sometimes made between segregation as being involuntary (such as due to laws) and/or partial and separation as being a voluntary and/or a more complete process, which may imply territorial separation of the different groups into different, homogeneous territories.
See also White separatism.