aberrant

Short definition from Wiktionary

Adjective

1. 1
   Differing from the norm.
2. 2
   Straying from the right way; deviating from morality or truth.
3. 3
   Deviating from the ordinary or natural type; exceptional; abnormal.

Noun

1. 1
   A person or object that deviates from the rest of a group.
2. 2
   A group, individual, or structure that deviates from the usual or natural type, especially with an atypical chromosome number.