Aberration

Aberration: (1) A deviation or irregularity. For example, a chromosome aberration is a deviation from the normal chromosome number or the normal chromosome structure. In this sense, aberration is also synonymous with deflection, departure, divergence, diversion, turning. (2) A mental aberration is a significant deviation from normal mental activity. In this sense, aberration is synonymous with mental derangement, mental illness, psychopathy.