A departure from what is normal, usual, or expected, typically an unwelcome one.

असामान्यता

English Usage: The scientist noted a psychological aberration in the subject's behavior during the experiment.

Hindi Usage: वैज्ञानिक ने प्रयोग के दौरान विषय के व्यवहार में असामान्यता का अवलोकन किया।