əˈbɛrənt
adjective
departing from an accepted standard or normal course
The word 'aberrant' is often used to describe something or someone that deviates from the norm or is unusual in some way. It can be used in various contexts such as psychology, biology, or even social behavior.
We can, I think, account for this fact only by looking at aberrant groups as forms which have been conquered by more successful competitors, with a few members still preserved under unusually favourable conditions.
Charles Darwin
The Origin of Species