ab·er·rant 
(ăbər-ənt, ă-bĕr-)
(ăbər-ənt, ă-bĕr-)adj.
1. Deviating from what is considered proper or normal: aberrant behavior.
2. Deviating from what is typical for a specified thing: an aberrant form of a gene.
n.
One that is aberrant.
[Latin aberrāns, aberrant-, present participle of aberrāre, to go astray; see ABERRATION.]
aber·rance, aber·ran·cy n.
aber·rant·ly adv.
Usage Note: Traditionally, aberrant is pronounced with stress on the second syllable (ă-bĕrənt). A more recent pronunciation, with stress on the first syllable (ăbər-ənt), has begun to compete with the older one. In 2009, 57 percent of the Usage Panel preferred the newer pronunciation and 43 percent the older. Nonetheless, both pronunciations should be considered acceptable.