Answer:
offensive and unwanted thoughts that persistently preoccupy a person
Step-by-step explanation:
Obsession is a condition in humans of being obsessed with certain things or some persons. It is a thought or idea which preoccupies the human mind persistently. Obsession is the product of one's own mind. Obsessed persons constantly think about somebody or something which worries them a lot. it is an unwanted thought and impulses that keeps on reoccurring in the human mind.